Unknown Cause Of Death

[xxBarneyxx]

My Mother in-law to be has recently set up a tropical tank. Its around 15g and has a UGF and small internal filter.

I did a fishless cycle on it and everything went as normal. After the cycle was finished we put in 6 very small tiger barbs, 6 neon tetras and an apple snail.

About a week later we added 3 small albino corys and 3 very small endlers (1 male/2 females) these came from a different shop.

The male endler and 1 female died within about 3 days and the last one is not looking to good, one of the corys have also died and the other two aren't moving around much.

I have been constantly checking the water stats and they have consistently been 0 ammonia, 0 nitrite and <5ppm nitrate. Have done a few water changes just in case but just cant think what the problem could be. There is no signs of damage to the fish, all look healthy and where eating and there is no aggression from the tiger barbs. There has been no ammonia spike and all the first batch of fish are still doing fine so the only thing I can think of is that there was maybe an issue with the livestock and/or the fact that they are all extremely small and just the shock of transferring was too much.

All the fish where acclimatised for over an hour.

Any thoughts? Its the first lot of fish that she has had and after convincing her that it would be much better to let me fishless cycle the tank first its really disappointing that she has lost some fish already.

 

[jmkgreen]

Possibly a dud test kit?

Only thing that looks remotely odd is the lack of nitrates. Did these rise prior to a water change?

Tank temperature correct? Lack of oxygen?

 

[xxBarneyxx]

Dont think its the test kit as it appeared to be working fine while cycling the tank (unless for some reason the low end of the ammonia scale isnt showing up). Temps been around 26degrees but has got a bit higher on a few days because of the weather.

Nitrate did go higher during the cycle but done a larger water change and it has had regularly water changes since. Despite what sounds like a lot of fish they are all really very small so there isnt actually much bioload in the tank at all for the nitrate to go up that much at the moment.

Could be lack of oxygen (due to the hot weather) but there has been no signs of that in the fish (no heavy beathing, hanging near the surface, etc). I did move the internal filter up so the outlet is just under the water surface to get more movement so if it is that this should hopefully sort it out.

 

[snowflake311]

I just lost 10 cory cats with in a month. Awful I know. First 7 were fine for a week then slowly all died off in the holding tank. So I thought it was. Bad batch of fish so I bought some more lost 2 more. I still have 3 schwartz they are doing ok. My water is the same as you I do water changes every 5 days. All other fish in the tank are still happy and healthy.

I think stress might have been caused. Stress from other fish, different ph, temp change, and just the big move to a new tank. I think cory cats are sensitive to stress.

Sorry for your loss it suck but it's all part of the hobby. You win some you lose some.