What's wrong with my chili rasboras?

[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!

 

[alto]

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.

 

[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?

 

[zozo]

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..

 

[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.

 

[alto]

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

 

[dw1305]

Hi all,

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.

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

 

[dw1305]

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



cheers Darrel

 

[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!

 

[dw1305]

Hi all,

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

 

[Aqua360]

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

 

[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

 

[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.

 

[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?

 

[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.