Dying Fish - Unknown Cause

[esupi]

Hi,

Hoping you might have some advice for me. We've been running a tropical tank for about a year now. We don't seem to have much luck with guppies (they all die after about 5-6 months) but otherwise we've only had a couple of casualties. Until the last few days. I've filled out the required info from the newbie thread below.
Tank size:64L
pH:7.8
ammonia:0
nitrite:0
nitrate:15
kH:I don't know what this is
gH:I don't know what this is
tank temp:26 degrees

Fish Symptoms (include full description including lesion, color, location, fish behavior): sudden death! no other abnormal behaviour whatsoever.

Volume and Frequency of water changes:approx. 15 % weekly.

Chemical Additives or Media in your tank:none.

Tank inhabitants: Initially, 3 neon tetras, 3 black phantom tetras, 4 bleeding heart tetras, 2 male guppies, 1 very small catfish-type fish (not sure what exactly), 1 sucking loach (I know he is too big for the tank now, but we were advised in the early days that he would be suitable! he's only grown to about 10 cm, and the tank had been stable at this stock level for 2-3 months).

Recent additions to your tank (living or decoration): 10 days ago, we purchased an additional 4 neon tetras ( to replace 3 guppies which had died over the previous months). We also added two small plants.

Basically, over the first week, 3 of the 4 new neons died - we didn't worry too much about it as they were new and probably stressed. we did do an extra water test and found nitrates to be high (approaching 40), so did an extra gravel vac and water change. At the end of the first week, one of the guppies died - again, we didn't worry too much as these are the longest surviving guppies we've had anyway and we thought it was normal. But then 2 days ago the 2nd guppy died, and then this morning we found a black phantom floating. This has really got us worried now as the phantoms have been there for about 9 months quite happily. All the fish still in the tank at any time have seemed perfectly normal - no signs of changed behaviour of disease of any kind.

I hate the idea that we might be doing something to cause them pain or suffering, and want to do all I can to avoid losing any more. Any ideas?

Many thanks.

esupi.

 

[Littlemonkey]

I think that by looking at your stocking that 15% weekly water change is not going to make much of a difference. I would go for at least 50% and maybe re-home the loach or get a much larger tank.

 

[WILDER]

Your tanks overstocked.
What test kit are you using?

Is the small catfish a cory fish.

Any signs of fish look pale or darker in colour.
Do any fish act listless and lethagic.
Any fish tilting to oneside when resting.
What does it look like when your fish go to the toilet.
Any fish look bloated or thin.
Do any fish have enlarged anus, or red inflamed anus.
Any sores ro red steaking on the fish body.
Any signs of darting, flicking and rubbing, excess mucas, laboured breathing.

 

[esupi]

Thank you for your replies.

Littlemonkey, if the water changes weren't working, wouldn't we see a rise in nitrates in the tank? We test the water weekly and it has been pretty stable always after the first couple of months. We don't have space for a bigger tank currently - I didn't know you could rehome fish? The loach spends almost all of his time hiding in an ornament we have anyway....

As for stocking - both shops we have purchased fish from have told us that this is the limit. Also, it doesn't seem to be outside the range of recommendations I've been able to find online (although the advice available is very varibale and vague). Is it possible that overstocking could have caused such a large number of deaths, as we now have two fewer fish than we started with, which had been stable for some time. What is the mechanism for overstocking causing death? Obviously, I wouldn't intentionally have done this.

The test kit we are using is an API freshwater kit.

Yes - the catfish is a cory - a panda one (just googled it)!

As for all the other questions - there really isn't anything different in any of the fish at all - no swimming on their sides, no sores, mucus, etc etc - they all look normal (as did the black phantom until we found him dead this morning). The only one strange thing we have is one neon which spends most of its time in a corner behind the filter in a vertical position with its head down. However, it has been doing that for about two months (I would guess) and for all that time has looked as if it has suffered some damage to its tail, which we assumed was causing the odd swimming behaviour. This isn't anything new though since adding the new fish, and this one is still alive too.

I really hate seeing the fish die because I'm doing something wrong, so anything I can learn to look after them better is much appreciated.

Thanks.
esupi.

 

[WILDER]

Overstocking tanks can cause stress and desease.

Always research the fish before you buy. For tank size, compatability, adult size.

The neon is the red stripe area still vibrant red.

Headstanding, odd swimmng, can be a bacterial infection of the swim bladder.

What do you feed your fish.

I would feed some shelled peas to your fish.

 

[esupi]

Thanks Wilder. I do try to do research, but there's never a clear-cut answer so I guess there's bound to be an element of learning by trial and error too. Certainly in the early days I was far too trusting of the fish shop's advice!

Yep the neon's red stripe is still vibrant. He just has a bulge between his body and his tail now, which is a slightly darker red (difficult to describe) - I thought that might be the result of some impact/trauma at some point.

They generally just get fed flakes. I did try shelled peas once before when I had an ill fish, but they were eaten by all the other fish and not the ill one - still - definitely worth another try.

Thanks!

 

[WILDER]

I think I would try a bacterial med.

Improve the fish diet with frozen foods, and veg.
Dried foods can lead to bloating, swim bladder, constipation.