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Losing Glowlight Danio’s

K

KirstyF

Member
Joined
25 Jul 2021
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664
Location
Kidderminster
I’m losing my glowlight danios and can’t figure out why.

I’ve been trying to do some research before posting but not finding any real answers.

They have been in tank for two weeks. Seemed to settle in ok. Eating fine, nothing to raise alarm bells.

Had a 1hr journey from the fish store (highly respected establishments) did a 25min float with bag still closed (inflated with oxygen) then around 1hr of acclimatisation, adding a small amount of tank water every five minutes. PH in bag was 0.1 different from tank when I popped the fish in.

Not seen any signs of the usual signs of Ill health. No marks, spots, flicking, flashing, abnormal swimming/floating. No redness around gills or abdomen. No lethargy or gasping and still interested in food.

But my numbers are dropping.

I’ve only found one dead fish (minus its head) and have done as thorough a search as is possible in a heavily planted tank and cannot find any other corpses. I’m assuming they are well hidden or have been eaten.

All other fish are fine and behaving completely normally.

The only thing that is a little odd is some fairly frantic swimming that I have observed today. Only in these danios (After WC - Used Seachem Prime as usual). Cardinal tetra, CPD’s, Peacock Gudgeon (added at the same time as the glowlight’s) Otto’s and SAE’s all good.

Danios are usually pretty zippy but these do seem especially frantic, racing from one end of the tank to the other along the front glass. I don’t know if they are reacting to something in the tank or stress of being disturbed during W/C and cleaning.

Not always easy to count in a large planted tank with active fish (they don’t school closely) but I’m convinced that I’m at least half a dozen down now and I’m at a bit of a loss!🙁

I’ll see if I can upload a video. Just gotta go figure out how to do that!
 
Well I would have said not possible. The tank has glass covers, glass bracing all the way around the edge of the tank, a hood, and I’ve never seen a fish on the floor.

However, the glass covers are always open a wee bit, as I have cables going in to my gyres and hey, an inch or two for oxygen circulation is a good thing right!! and, of course, there are cut outs around the inlet/outlet pipes so I’ve just been to check.

A flashlight underneath the cabinet revealed two desiccated corpses.

I’m pretty upset with myself right now. Just never occurred to me that they could/would get out of such small places. I’ve got val’s at surface at one end (waiting for val’s to gain height to surface level at the other) and salvinia are spreading. I’ve also got a couple of good floating patches of whatever the plant is that looks like giant hydrocotle, but close to 70% of the tank surface is still open.

I’m gonna close the lids as far as I can get them and maybe try to lay something over the gaps.

Any other ideas? Really not feeling like a very good fish mummy at the minute. Here I am looking for signs of disease and they’re jumping out of the damn tank. 😢

Really appreciate that shout though guys. At least I know what’s going on now.
 
GHNelson said:
Lower the water level a couple of inches!
Click to expand...

Doing so as we speak.

Can’t believe I missed this! Always had lidded tanks. Never had jumpers. You think ur doing everything right….until you’re not.

Is there any particular reason you know that they would jump, other than maybe stress in a new environment, or is it just a tendency for these fish?
 
Hi Kirsty
They are very active and are startled very easily and they are know as jumpers!
Probably the fish store should have a label stating these fish have a tendency to jump out of aquariums!
 
GHNelson said:
Hi Kirsty
They are very active and are startled very easily and they are know as jumpers!
Probably the fish store should have a label stating these fish have a tendency to jump out of aquariums!
Click to expand...

Yes, a heads up would be good.

At least, now I know, I can manage accordingly and not lose any more.

Really appreciate your help, and @Wookii too.
 
Easy to imagine that zooming around in the new tank might have lead to an upward trajectory when encountering a pane of glass they aren't used to. That lines them up perfectly with any edge gaps from lids!
 
I had a group of these for about 8-10 years (they live surprisingly long for danios) and they moved tanks a couple of times in that time. I found to begin with they were very jumpy and quite frantic but they settled down and became much calmer, to the point they wouldn't jump even in an open top. Some of that might be luck but I did have a lot of surface cover.
As they aged they became more secretive and rarely grouped together. They also became a little ornery but my tank was far smaller than yours.
 
mort said:
I had a group of these for about 8-10 years (they live surprisingly long for danios) and they moved tanks a couple of times in that time. I found to begin with they were very jumpy and quite frantic but they settled down and became much calmer, to the point they wouldn't jump even in an open top. Some of that might be luck but I did have a lot of surface cover.
As they aged they became more secretive and rarely grouped together. They also became a little ornery but my tank was far smaller than yours.
Click to expand...

Thanks @mort. It’s good to know they might settle down a bit given time.
I think extra surface cover may help. My current cover is increasing slowly but there’s a bit to go yet. I might just invest in another batch or two to speed things along.

Mine haven’t grouped all together from day one. They tended to be off in smaller groups of 4 or 5, which is exactly what my CPD’s did, and they couldn’t be happier little fish. Go figure!!

I do wonder if it will also help in a larger tank to increase numbers slightly as they can get a bit lost in there. I’ll maybe take the shoal up to 25? And this may help to calm them too. I’ll also leave it a good couple of weeks or so before I do any major re-planting or tank disturbance……and then I’ll watch them like a hawk.

I can’t see why the tank wouldn't be a pretty good environment for them in the long term but don’t want to make any more mistakes.

Any other tips welcome. 😊
 
I originally got ten and bred them up to about 20 and kept the group around that. They do like safety in numbers and it helped diffuse the interspecific aggression, so upping the group size is definitely a good idea for me. Mine were kept with hengeli rasbora which I think acted as dither fish, although they to can be shy to begin with.

Trigonostigma hengeli — Seriously Fish

www.seriouslyfish.com www.seriouslyfish.com
 
Thank you for that suggestion @mort .

I’ve got 22 Cardinal Tetra and 30 CPD’s as my larger groups, as well as smaller groups of Peacock Gudgeon and otto’s and 3 SAE’s so, with the glowlights, I think I’m probably maxed out on stocking.

I don’t think the smaller groups are adding much from a ‘dither fish’ point of view but hopefully the tetra and CPD’s with the slightly larger group of glowlights will be enough.

I did a pretty big clean up last weekend, pulling inlets, outlets, spraybars and gyres out for a bit of a scrub so, in retrospect, I think that was pretty shoddy timing too. 🙁

Will try to get some new additions as soon as poss and then minimise disturbance for a few weeks.
 
KirstyF said:
I’ve got 22 Cardinal Tetra and 30 CPD’s as my larger groups, as well as smaller groups of Peacock Gudgeon and otto’s and 3 SAE’s so, with the glowlights, I think I’m probably maxed out on stocking.
Click to expand...

That's showing great restraint - I'm always fighting against the stocking limit for my tanks - I always want so many different fish! You're at about 50% of max stocking right now according to AqAdvisor:

AqAdvisor - 84" x 24" x 22"
 
Wookii said:
That's showing great restraint - I'm always fighting against the stocking limit for my tanks - I always want so many different fish! You're at about 50% of max stocking right now according to AqAdvisor:

AqAdvisor - 84" x 24" x 22"
Click to expand...

Thanks @Wookii. That’s a really neat site, I’ve not used before.

I guess the ‘standard’ stocking calculations are pretty old school these days.

My tank gives me 160” based on 1” per gallon and 168” based on 1” per 12sq” of surface area so that was my rule of thumb numbers.

I’ve got a dozen otto’s that would need to be added to the AqAdvisor calc but still sitting well within their limits which is good to know.

Though of course, this could now be me next time I’m at the fish store 😍🐠🐡🐟

👍
 
KirstyF said:
Thanks @Wookii. That’s a really neat site, I’ve not used before.

I guess the ‘standard’ stocking calculations are pretty old school these days.

My tank gives me 160” based on 1” per gallon and 168” based on 1” per 12sq” of surface area so that was my rule of thumb numbers.

I’ve got a dozen otto’s that would need to be added to the AqAdvisor calc but still sitting well within their limits which is good to know.

Though of course, this could now be me next time I’m at the fish store 😍🐠🐡🐟

👍
Click to expand...

Yeah the fish length to volume rules don’t really hold true much of the time - for example a 6 inch long Discus is going to contribute a lot more biomass than, say, 6 x 1” Rasbora. I assume that AQAdviser site takes account of adult fish mass and other factors to determine the contribution of each fish species.
 
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