# What's wrong with my chili rasboras?



## Dr Mike Oxgreen

There is something wrong with my chili rasboras - they are definitely unhappy, but I can't work out why. When the lights are on, they spend their whole time frantically swimming up and down the glass in one corner of the tank. The corner they've chosen happens to be near the filter outflow, so they have to swim very hard, although other parts of the tank do not have such strong flow. They are pale. They look distinctly stressed. They are not at all fun to watch, because they look so distressed.

The tank is a 25 litre nano tank, 40x25x25 cm. Filter is an external canister (Eheim 2211) with water returned via a lily pipe. I set it up in November, and began cycling it. Near the end of December I was satisfied that the cycling was complete, and I planted my plants. About the second week in January I added 7 chili rasboras, 9 blue velvet shrimp and 3 otocinclus. About a week later I added a dozen more of the blue velvet shrimps. I have also added a bamboo shrimp.

Here are the water parameters:
NH3/NH4: 0
NO2: 0
NO3: about 20-30 mg/l
pH: 6.5
KH: 3°
GH: 5°
TDS: 124 mg/l
Temperature: 23°C

The tank has CO2 injection via a soda stream cylinder and an inline diffuser. The drop checker is down low at the opposite corner from the lily pipe. It is usually green (except today it's blue: see below). I am fertilising with TNC Complete, at a 50% dosage daily to approximate the same sort of nutrient dose as EI.

My lighting is, I admit, pretty bright: a 1200 lumen Beamswork LED light, and an 800 lumen 2x36cm Interpet LED. Also, it's worth noting that when the lights are off altogether the rasboras are calm, and at night they 'sleep' as you'd expect. But even if I switch just one of the lights to its 'moonlight' setting (which is very dim indeed), within minutes the rasboras are beginning to mill about in that corner. So I don't think the problem is due to bright lights, because they do it even when the lighting is very dim.

Today as an experiment I have switched the CO2 off, and run an air pump to drive off the CO2. The reduction in CO2 has made no difference to the behaviour of the chilies, so I don't think it's an issue with CO2. *But*, and this is very strange, whenever I switch the air pump on the chilies *immediately* stop, move towards the centre of the tank, and begin behaving much more naturally. This happens within a few seconds, so it can't possibly be anything to do with the aeration effect. It doesn't eliminate the unnatural behaviour completely, but it has a definite and immediate effect. The effect is somewhat temporary, though - they gradually resume their frantic pacing up and down the glass.

I have tried putting a piece of black paper up against the glass at the end where they do this, but it had no effect. An experiment I intend to try is to place a piece of black plastic or rubber *inside* the tank, so that they can't possibly be seeing any reflections in the glass. Haven't done this yet; will report the results when I do.

The chilies have been in the tank for more than a fortnight, so they really should have settled in and coloured up by now. But they're very pale indeed. They seem to have very red gills though - although most pictures of them do show red gills; it could simply be their pale body colouration that shows up the red gills more.

It's worth noting that I have suffered losses of the blue velvet shrimps, and the bamboo shrimp never feeds and just hides away all the time.

I will upload a video to illustrate this.

Any ideas?


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## Dr Mike Oxgreen

Here's a video link. Notice them frantically milling about in the top right corner. Notice also how pale they are...


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## Tim Harrison

Have you tried turning the filter off and then observing their behaviour? Chili rasbora are typically found in sluggish black water streams stained with tannins and shaded by overhanging vegetation - http://www.seriouslyfish.com/species/boraras-brigittae/


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## darren636

Mine hated co2 , bright lights and high flow


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## Dr Mike Oxgreen

Troi said:


> Have you tried turning the filter off and then observing their behaviour?


Good suggestion - trying it now.

The filter has been off for about five minutes so far, and there is no obvious change in the chilies' behaviour. They're still pacing up and down the glass with their noses pressed against the edge. The only difference is that they don't have to swim quite as hard to achieve this.

I'll keep it off for another twenty minutes or so to see if anything changes, but obviously I don't want to leave it too much more than that.

I usually use a mixture of rainwater and tap water, but last time I did a 50% water change about a week ago I used RO instead of the rainwater in case the rainwater has any pollutants in it. There hasn't been any improvement, although another water change is due tomorrow so I will once again use a mixture of RO and tap water. If necessary I dose a small amount of Epsom salt to tweak the GH up by a degree for the shrimps.


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## Dr Mike Oxgreen

darren636 said:


> Mine hated co2 , bright lights and high flow


Interesting. What did you do to solve the problem?

So are we saying that chili rasboras are not suited to a planted tank? CO2, bright light and good flow are three ingredients of many people's planted tanks.

Have I simply chosen the wrong fish?


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## Dr Mike Oxgreen

Or is it that I don't have enough of them to make them comfortable?

I'm switching my filter back on now. It hasn't really made a difference. 

Edited to add: I'm trying to allow some hornwort to grow along the surface to provide a bit of cover. I'm also trying to propagate some of it to plant into the corner, to see if I can discourage the little buggers from doing it!


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## darren636

Dr Mike Oxgreen said:


> Interesting. What did you do to solve the problem?
> 
> So are we saying that chili rasboras are not suited to a planted tank? CO2, bright light and good flow are three ingredients of many people's planted tanks.
> 
> Have I simply chosen the wrong fish?



I went completely low tech.
These guys are not suited to high tech.

I'm not saying some people don't have success.
Its not quantity - its a group behaviour issue.

I'd turn off co2 , reduce light intensity and reduce flow for a couple of days and see what happens, then gradually and slowly ramp it back up to high tech


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## Dr Mike Oxgreen

darren636 said:


> I'd turn off co2 , reduce light intensity and reduce flow for a couple of days and see what happens, then gradually and slowly ramp it back up to high tech


Okay, I'm going to give that a go. I've turned the 800 lumen LED off completely, and switched the 1200 lumen LED into its 'moonlight' mode which reduces the intensity to about a quarter. I've turned off CO2, and half-closed the shut-off valve in the outflow hose from the filter.

Goodness knows what this is going to do to my HC and Glossostigma, but I guess they'll recover. Will I get algae? Will my cryptocoryne melt?


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## john dory

Hi mike.
I've never kept chillis,but it took an age for my rummy nose tetras to blossom.
Like your chillis...they were pale and panicky...but they're as bold as brass now.
Nice progress on the tank btw.
P.s. what are your otos eating?


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## Dr Mike Oxgreen

That's encouraging! Maybe my chilies just need a bit of time and gradual acclimatisation. Will see how the 'low tech' period goes.

The otos are eating a chunk of boiled broccoli stem weighed down with a ceramic ring. They ignored it for 24 hours, but they're all over it now it's been in there for 48 hours. I think you've got to be prepared to leave vegetables for longer than you'd normally leave food, so that it goes nice and soft. Will have to take it out tomorrow though I think.


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## john dory

Ok thanks


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## Dr Mike Oxgreen

I had an idea last night. It might get me carted off to the loony bin though! 

I'm going to try making some decoy chili rasboras. Hobbycraft sell sheets of neoprene foam in various colours very cheaply. If I get a red sheet I could cut out some tiny rasbora-shaped pieces and use a thin black permanent pen to draw the black markings on them and an eye spot. Then thread them onto various different lengths of black nylon thread and tie them all to a weight. Drop that into the middle of the tank, _et voilà!_ A shoal of decoys, calmly hanging about. I think the neoprene foam is a closed cell structure, so hopefully they won't get waterlogged and will remain buoyant.

With any luck, a shoal of decoys placed in the middle of the tank will make them feel more at ease.

Section me now!!


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## darren636

That's a novel idea.

And quite mad!

I was pondering this issue last night.

You don't see people putting delicate liquorice gourami into high tech set ups,.boraras inhabit the same environments.
Just a musing.

Good luck with them.


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## Dr Mike Oxgreen

That's true, but there are lots and lots of species that originate from black water streams in the wild but are happy to adapt to clear, bright conditions in captivity.

I'll post some pictures of my handiwork when I've done it. Might not be today though.


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## royteo86

Hi bro try keeping frog bits that will help alot

Sent from my D6653 using Tapatalk


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## Dr Mike Oxgreen

royteo86 said:


> Hi bro try keeping frog bits that will help alot


Do you mean Amazon frogbit or something like that?

I have tried taking some floating plants from my pond. It's like duckweed, but has an attractive almost feathery leaf shape. No idea what it is (picture below, with bees drinking). Hopefully it will grow in the aquarium as well.

It's a bit of a balancing act though, because I have both HC and Glossostigma growing at the front of the tank and neither will enjoy being shaded (particularly the Glossostigma).


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## dw1305

Hi all,





Dr Mike Oxgreen said:


> No idea what it is


_<"Azolla caroliniana">._

cheers Darrel


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## darren636

I ordered some yesterday!


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## rebel

Dr Mike Oxgreen said:


> I had an idea last night. It might get me carted off to the loony bin though!
> 
> I'm going to try making some decoy chili rasboras. Hobbycraft sell sheets of neoprene foam in various colours very cheaply. If I get a red sheet I could cut out some tiny rasbora-shaped pieces and use a thin black permanent pen to draw the black markings on them and an eye spot. Then thread them onto various different lengths of black nylon thread and tie them all to a weight. Drop that into the middle of the tank, _et voilà!_ A shoal of decoys, calmly hanging about. I think the neoprene foam is a closed cell structure, so hopefully they won't get waterlogged and will remain buoyant.
> 
> With any luck, a shoal of decoys placed in the middle of the tank will make them feel more at ease.
> 
> Section me now!!


LOVE THAT IDEA.

If you lived near me, I would print this quote off and show it to the mental health team when they come to take you away. I will reassure them that your tank is in good hands.


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## dw1305

Hi all, 





darren636 said:


> I ordered some yesterday!


You could have had some of mine.

Just before Xmas I took some _Azolla_ into the University, and the students extracted the <"symbiotic, nitrogen fixing cyanobacteria"> (_Anabaena azollae_) from the leaf "pockets" (actual image below). 




 

cheers Darrel


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## darren636

Chloroplasts!

Are they a thing?
I seem to remember them from biology...


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## dw1305

Hi all, 





darren636 said:


> Chloroplasts! Are they a thing?


 They are, and they are what makes life on Earth possible for us. 

You need a copy of Colin Tudge's book <"The Secret Life of Trees: How They Live and Why They Matter">.

cheers Darrel


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## Dr Mike Oxgreen

I am prototyping the idea! Will the little piece of neoprene foam absorb water and sink overnight, or will it stay up?

Place your bets!!


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## Dr Mike Oxgreen

Thanks for the ID on that floating plant, Darrel!

My pond is covered with it, and I have to periodically scoop it out. It also seems to survive the winter, although it tends to go pinkish-red. It's just as invasive and fast growing as duckweed, but far prettier.

Update on my chilies... They've now had a day of very, very low lighting, no CO2 and reduced water flow. They are definitely looking a lot more relaxed and patrolling the tank a bit more. They're still schooling quite tightly, and I wouldn't say their tendency to pace up and down the glass has gone completely, but it's a definite improvement.

I have switched the CO2 back on, but at a much reduced rate. Tomorrow I will try upping the water flow very slightly. I also hope to make a shoal of decoys, which I will introduce before attempting to increase the light level. Will my filter cope with the extra bioload from 8 or 9 rubber chili rasboras? What should I feed them?

I can only count 6 chilies now, so either one is hiding or I've lost one, possibly to stress.


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## Dr Mike Oxgreen

I think I need to have a long, hard talk with myself, to figure out how my life has led to this...


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## darren636

They're all male !

Addendum.

Youre off your trolley!!!


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## Nelson

Doctor,you need to see a doctor .


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## Tim Harrison

Lol...awesome, you don't need the real thing any more...problem solved


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## darren636

What's the tank temperature.

Just noticed my new group in the q tank are glass surfing

Temperature at 30 degrees ! Oooops


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## Dr Mike Oxgreen

The chilies do seem to be spending a bit more time in the middle of the tank now that the decoys are there.

I also made a dimmer today, out of a couple of DC power connectors, some wire and a variable resistor. So I can now gradually increase the light intensity. The variable resistor is getting slightly warm; by my reckoning it should only be dissipating about a Watt, but maybe even that is beyond its spec.

I've ordered a proper LED controller so that I can ramp the brightness up and down when switching on and off - I think they work on pulse width modulation instead of resistance.

I've also restored the filter flow back to normal.


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## Dr Mike Oxgreen

Here's a picture. The rubber chilies are swimming at slightly strange angles - swim bladder problems? The screws were the best things I could think of to tie them down with!


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## Tim Harrison

Are they working?


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## Dr Mike Oxgreen

Troi said:


> Are they working?


It's a bit early to tell at the moment, but they might be working. One of the chilies in particular is spending a lot of time calmly strutting about amongst the rubber ones, and that fish has actually coloured up a bit as well! I'm really hoping his colleagues will follow suit.

I might actually make some more tomorrow, and possibly re-thread some of the existing ones onto longer threads so they swim a bit higher. My suspicion is that the chilies might gain confidence if there are other 'fish' swimming at higher levels in the water, and chili rasboras do naturally occupy the upper half of the water column I think. I'll try to make some smaller ones, because the ones I've made do dwarf the real fish somewhat.


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## Tim Harrison

Haha...he's got competition, this could turn out to be quite interesting, from a behavioural aspect.


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## amritc1

Excellent, you need to feed them 


Sent from my iPhone using Tapatalk


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## Heagney

What a novel idea, that's awesome! The lengths you go to eh


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## Dr Mike Oxgreen

Problem solved?

I am hopeful that I may have found the solution to my restless and panicky chilli rasboras. I've made three changes during the last week, and I think the combination of these changes might have worked.

The first change was to swap the lily pipe for a spray bar. The spray bar is a little too long and needs shortening, so it's at a diagonal across the back of the tank for now, with the the holes pointing upwards towards the surface and somewhat backwards against the glass to reduce the force of the flow. I also need some elbow connectors so I can put it at a more horizontal angle, probably near the bottom of the tank pointing upwards. Hoping to make these adjustments today during a water change. The chillies do seem to prefer the more diffused water flow.

I will need to experiment with the direction of flow to get decent CO2 distribution. My drop checker now goes blue in the mornings whereas with the lily pipe it previously stayed green, even when the CO2 had been off for many hours. This possibly indicates better surface gas exchange with the spray bar; I do think I've got a bit more surface turnover now despite the more gentle flow overall, which is no bad thing. I may also consider having a CO2 'on' period during lights-off simply to prevent the CO2 level going too low. The challenge will be to make sure that my foreground carpets of HC and Glossostigma get enough CO2 without creating strong currents that upset the chillies.

The second change seems to have had a significant effect: _more chillies_. Lots and lots more chillies! I went back up to Sweet Knowle Aquatics near Stratford Upon Avon a few days ago, which is the only shop I can find that has them in stock at the moment. Fortunately it's also a truly excellent shop for freshwater tropical fish - the quality of fish is quite the best I have come across in several decades of visiting fish shops. Well worth visiting!

I decided to get another *dozen* chillies to add to the six already in the tank. I know that's a huge increase, but I'm confident the tank can take the extra bioload - it is quite heavily planted and has a canister filter full of ceramic balls with a rough surface for bacteria. I will monitor ammonia carefully as the tank adjusts, and add an occasional dose of Prime as a precaution.

On the day after adding the newcomers the chillies did look quite a bit more chilled. They have dispersed a bit more, and are not constantly chasing up and down the sides of the tank or hiding in a corner.

Aesthetically it's not quite what I was aiming for with the tank: I originally wanted just a very small number of tiny fish to set off the planting and give my nano tank an illusion of scale, but I'd far rather have a larger number of relaxed fish rather than a small number of panicky fish. I have removed my ridiculous rubber fish! I don't think the real chillies were impressed by them anyway.

The third change I believe has made things better still for the chillies' stress level. I have installed an LED controller, which ramps the lights on and off over a configurable period of time as well as allowing me to limit the maximum brightness if I need to. With this, it seems I can ramp the lights up over a few hours all the way to full brightness and the chillies don't seem to care.

I didn't realise that the controller I ordered only allows a single photo period per channel, so I bought some 5.5x2.1mm DC plugs and sockets from Maplin and made a connector that links two plugs and two sockets together. There was much swearing yesterday because my soldering skillz are so poor, but I got there in the end! I can now plug both lights into both channels 1 and 2 of the LED controller, effectively giving two photo periods for both lights together instead of controlling the lights independently. I will find it useful to have a short lighting period in the morning (which I have configured much dimmer than the main period) so that I can feed the fish when I get up. I have configured the main photo period to ramp the lights up over a 4 hour period and then immediately back down over 4 hours; I can reduce the ramp period to 2 hours if all goes well. The controller has a third channel, which I'm not currently using.

Oh, and there is one other 'change' that has been happening over the last week or so: I've been allowing the hornwort to grow unchecked, and it's now formed quite a thicket of floating strands at the surface which is beginning to fill the tank top-down. I will prune and replant some of it so that it's not choking the aesthetic picture of the tank, but keep some of the surface cover in case that's part of what's making the chillies more relaxed.

At last, the chillies are doing what chillies should do: they strut around the middle of the tank like minuscule aquatic chickens, rather than charging around like mental cases. They're not schooling as tightly as they were, which although it was aesthetically pleasing it did indicate an element of stress. Some of them are beginning to colour up a bit as well.

Happy days, I hope!


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## Dr Mike Oxgreen

Are chilli rasboras meant to go mental over algae wafers?


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## darren636

Dr Mike Oxgreen said:


> Are chilli rasboras meant to go mental over algae wafers?



Mine did, for the first couple of times


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## Dr Mike Oxgreen

Just a brief update on this, because it turns out I hadn't completely cracked the problem when I last posted, but I really do think I understand the problem now.

When I last did a prune of the hornwort and other stem plants, the chillies immediately became nervous again, and started milling about at the back of the tank and at one side. Reducing light intensity didn't help. Since then I've let the hornwort grow unchecked for about 10 days, during which time it has gone a bit mental - and a few days ago the chillies suddenly decided to occupy the centre of the tank underneath the thicket of hornwort, and are calmly and slowly strutting about just the way they should. I have increased the brightness of my lights to 100% (2000 lumens) to compensate, in the hope of ensuring that enough light reaches the HC and Glossostigma, and still the chillies are chilled.

So I'm now 100% sure that lighting is not the problem _per se_. Previously I've tried reducing the lighting right down to very low intensity, and it didn't help - and now I've got it at 100% and the chillies are fine.

The change to the flow (swapping the lilly pipe for a spray bar) helped a small amount.

But I now think the real key is surface cover. It seems that chillies don't like open surface. The challenge for me now is to find a way of pruning the hornwort so that it provides fairly thick surface cover but doesn't block your view into the tank. At the moment it is rather spoiling the tank because you can't see to the back at all, which is a shame because the _Pogostemon erectus_ at the back is doing rather well now that I've increased my fertilisation regime.

I have also tried a different floating plant _(Azolla caroliniana)_, but the problem with that is that whenever I prune the HC and Glossostigma it's impossible to net out the prunings without removing the Azolla as well. The advantage of hornwort is that it doesn't completely block the light.

I think I'll now start pruning the hornwort one or two stems at a time, trying not to upset the chillies but trying to improve the view into the tank. Perhaps I can reduce its thickness gradually enough that the chillies either won't notice or won't care.

You should see the way the floating hornwort stems pearl under the full intensity of the lights!


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## alto

Dr Mike Oxgreen said:


> I have also tried a different floating plant _(Azolla caroliniana)_, but the problem with that is that whenever I prune the HC and Glossostigma it's impossible to net out the prunings without removing the Azolla as well.


I just net out my small floaters first, then do tank maintenance  - usually need to thin out the floaters anyway (though I have _Salvinia natans_ rather than the _Azolla_)

You might try some of these small floaters rather than the hornwort - should be easier to control the degree of shade & won't impact your scape view as much.


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## Dr Mike Oxgreen

Ah yes, _Salvinia natans_ is indeed a lovely plant. A type of fern, I believe. Might well try that.

So I assume you net the floaters out into a holding container, do the pruning of other plants, net out the clippings and discard them, then put the floaters back in?


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## zozo

Dr Mike Oxgreen said:


> Ah yes, _Salvinia natans_ is indeed a lovely plant.



It is, you can find it in any garden centers pond section when this season starts.. Tho you'll get the full grown big version for a few pennies..  But you can put the big version in a bowl in the garden and clip off young tiny growth to put in the tank. That's ho i started with it  with clippings from the pond.. In a well fertilized tank it multiplies so fast it doesn't get a chance to grow big. It realy is a one in a life time buy as long as you keep a few it'll grow back and keep on growing. Unstoppable bugger. It's like duckweed but only bigger and easier to control.

If you have Amano shrimps then it'll be fun to watch.. They love it and come up cling to it and sink down to the bottom with the salvinia between their paws like a little parachute. And a few cm before hitting the bottom they let go of it, make a few loops back to the surface and grab another one. 

Salvinia and Amano shrimps is guaranteed circus in your tank..


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## stu_

Vallis Nana has narrow leaves that wouldn't ruin the sense of scale,but would be long enough to grow up to the surface then across.Where's the flow going?
The only problem if it takes off,is that it can get a bit invasive.


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## alto

Dr Mike Oxgreen said:


> So I assume you net the floaters out into a holding container, do the pruning of other plants, net out the clippings and discard them, then put the floaters back in?


Yes


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## dw1305

Hi all,





Dr Mike Oxgreen said:


> But I now think the real key is surface cover. It seems that chillies don't like open surface. The challenge for me now is to find a way of pruning the hornwort so that it provides fairly thick surface cover but doesn't block your view into the tank.


I think this is true for nearly all small fish, being in the open is a stressful experience. I'm a Hornwort fan, it is easy to prune, and small fish really like it. _Ceratopteris thalictoides_ is a sub-surface floater that is easier to control. Have a look at <"60P IWAGUMI...."> for comment on small fish and bare tanks. 





Dr Mike Oxgreen said:


> Ah yes, _Salvinia natans_ is indeed a lovely plant. A type of fern, I believe. Might well try that.


I've got plenty spare, we don't quite know what the species sold as_ Salvinia natans _is, but _Salvinia_ "auriculata group" covers it.

These are the changes in morphology that Marcel was talking about. This is when it is enjoying itself with plenty of light and nutrients.



and this the same plant looks with less light and low nutrients




_Salvinia_ has short "roots" (really a modified frond), if you want a plant with longer roots, either _Pistia stratiotes_ or _Limnobium laevigatum _have longer roots. The best roots are probably on _Pistia,_ but _Limnobium_ is also good, and allows you to use the <"Duckweed Index"> for nutrient addition.

Again I always have spare _Pistia_ and _Limnobium._

cheers Darrel


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## dw1305

Hi all,
Mike have you seen "Akwascape's" tank in <"Cryptocoryne parva carpet">?



 

cheers Darrel


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## Dr Mike Oxgreen

Oddly, once the chillies had got used to calmly strutting about underneath a dense thicket of hornwort, they have continued to be happy despite my gradually thinning the hornwort very considerably - to the extent that there's now substantial clear water surface and open space in the middle of the tank. And they are colouring up very nicely, with a good handful of (presumably) males sporting an increasingly intense red.

So it appears that they wanted a period of dense cover, but now they don't really care.

I don't understand the workings of the tiny brains of these little fish!


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## dw1305

Hi all,





Dr Mike Oxgreen said:


> they have continued to be happy despite my gradually thinning the hornwort very considerably - to the extent that there's now substantial clear water surface and open space in the middle of the tank. And they are colouring up very nicely, with a good handful of (presumably) males sporting an increasingly intense red.


Brilliant and the tank looks great.

cheers Darrel


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## Aqua360

Dr Mike Oxgreen said:


> Oddly, once the chillies had got used to calmly strutting about underneath a dense thicket of hornwort, they have continued to be happy despite my gradually thinning the hornwort very considerably - to the extent that there's now substantial clear water surface and open space in the middle of the tank. And they are colouring up very nicely, with a good handful of (presumably) males sporting an increasingly intense red.
> 
> So it appears that they wanted a period of dense cover, but now they don't really care.
> 
> I don't understand the workings of the tiny brains of these little fish!



glad to hear they are well, also that is an awesome set-up; well done


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## Richard Dowling

This may help my current issue...I set up an Iwagumi with no cover and my fish appear to hate it. Perhaps I need a floater plant which I can slowly remove.

Sent from my D6503 using Tapatalk


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## Lindy

1st time I have seen decoy rubber fish, brilliant! I have a large shoal of chilis mixed with Maculates and another I can't remember. They have floaters most of the time but their behaviour doesn't change when I scoop them out. I wonder if this is down to my tanin stained water though? If you don't mind the colour you might want to drop a rooibos teabag in your tank and get a bit of colour about it.


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## Dr Mike Oxgreen

Out of interest, does anyone know if chili rasboras _(Boraras brigittae)_ and phoenix rasboras _(Boraras merah)_ hybridise?

I'm curious about the markings of mine. In total I have 14 of them, of which I'd say three or four have the 'classic' chili rasbora markings and colouration: a long, unbroken lozenge-shaped black stripe along the whole of the fish's flank, all the way to the tail, that widens towards the front, and an overall intense red colour. But there are also three or four that I'm convinced aren't chili rasboras at all, but are actually phoenix rasboras: they don't have a line, and instead have an isolated oval black spot on their sides roughly between the pectoral fins and the dorsal fin, with a much less intense red colour and the body is somewhat more translucent.

But interestingly the rest of the fish have varying degrees of markings in between: some have the lozenge-shape mark but the black line stops and doesn't extend to the tail, and others have a line extending to the tail but it is broken along the way. All the fish group and shoal together.

I don't know whether these fish are tank bred or wild caught, but I've read that importers often do mix the two species together.

But it's the intermediate markings that interest me. Is it possible that these two species can hybridise? Or are these differences due to gender dimorphism? Or just individual variation, or perhaps differences due to their position in the pecking order?


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## darren636

The brigittae/merah hybrids are documented as being sterile- but they can reproduce together.
Also,  merah and brigittae overlap geographically and some mimicry has been observed, also, there are possible 'undescribed' species in these collection zones.

In short,  its a mess.


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