Old and new tetra dying

[ooooooooo]

Hello everyone - I've just joined after a web search, this seems like a valuable forum and I hope someone can help!

I have a 70 litre/18 US gallon treshwater tropical tank.


Prior to this weekend my stock was:
2 clown loaches
1 sucking loach
4 full grown mollies and some small ones (breeding like rabbits)
2 cardinal tetra

It was somewhat depleted from deaths due to old age, so I decided to buy some new fish. I bought:

3 cardinal tetra
3 zebra danios
1 armoured shrimp

Since the weekend, 1 of the new tetra and both of the old tetra have died suddenly. The deaths of the two old tetra were quite sudden, no loss of control etc. beforehand - just found dead on the bottom of the tank. The dead new tetra's body hasn't been found, but was very small and may have been eaten quickly.

The possible causes I can think of:

1. armoured shrimp killing them (but not eating them - bodies found intact)
2. the now-dead new tetra carried a tetra-only disease and passed it on
3. a new tetra has been killing the others - seems unlikely, all new tetra were significantly smaller than the older ones
4. too many fish - but the danios and small mollies are fine
5. another fish is killing the tetra - danios?!

Can anyone comment on the possibility of each of these, or another cause? I don't have a nitrite test kit handy. It is a very old established tank (6 years), I have a substantial external filter and the tank is well planted. I will try and get hold of a nitrite test, just to see.

Many thanks,
Ben.

 

[cloud]

I haven't kept tetras in a while so wait for some more replies from other people, but it sounds like it would be a tetra only desease to me. Cardianals tend to shoal so it should'nt matter what size they are related to each other, and they're too quick for shrimps. Also tetras are more prone to speciese only desease. There's a common one called Neon Tetra Disease (which I believe cardinals can get too) which kills them off without warning and does'nt effect the rest of your fish.
I'm afraid I don't think there's much you can do about it but maybe someone can correct me on that.

 

[ooooooooo]

My tank is going crazy!

Thanks Cloud - I had vaguely heard of something like that somewhere, thanks for reminding me!

Things have developed a bit since this morning.

First, another new tetra has disappeared.

Second, I've noticed the two clown loaches FIGHTING. The orange goes dark and the black goes greyish. They nip at each other's mouths and make clicking noises. They are normally such good friends!

I read this page:

http://fins.actwin.com/aquatic-plants/month.200009/msg00911.html

Seems some randy clowns made a meal of some danios. I wonder if that's what is happening here? I only found bodies of the two large tetra, the smaller ones have disappeared - perhaps they can only swallow the small ones? Also, the largest of the dead tetra was covered in about 10 snails. This strikes me as odd, snails have never attacked the bodies of dead fish in my tank before.

I'll definitely check the water quality as there is some indication that loaches breed when the water quality drops (perverse...)

If it is a disease, would it be reasonable to expect the shop to provide some new tetra?

This is certainly an exciting time for my tank... no wonder the shrimp spends most of his time hiding Even the mollies are staying out of the way at the moment.

Ben.

 

[OrionGirl]

Testing the tank is crucial. There are many issues here--beginning with fish from a wide variety of water parameters, and overstocking. Since clowns can get to 12 inches, they will eventually need a much larger tank. The addition of several fish at once may have caused a brief spike, compounded by the deaths, causing other issues. How did you acclimate the new fish to your tank?

With NTD, there is a significant loss of color to the fish prior to death, so unless you saw those symptoms, I would doubt that was a cause.

Most snails are detrivores--they will eat anything and everything.

 

[ArkyLady]

Even though with the original fish the tank was likely fully established/cycled, adding the new fish causes additional load to your bacterial filter. Until your bacteria multiply enough to handle the extra wastes of the new fish, you can get ammonia and nitrite spikes that can be harmful or deadly to your fish. If you are unfamiliar with the cycle process, read the Cycle sticky thread at the top of the newbie forum for more details.

Tetras aren't very hardy fish and can die easily from ammonia and nitrite being too high. This would be my first guess anyway as to what is happening. Another problem you will have is the clown loaches will grow very large, too large for an 18 gallon tank. They get to about 12" long.

My suggestion would be to try to find a more suitable home for the clown loaches (back to LFS or give to a friend or a larger tank for yourself). Monitor all your water levels, especially ammonia and nitrite. If ammonia is over 1ppm, or nitrite is over .50ppm, then do a 50% water change. Even if you're having to change the water every day or a couple of times a day to keep them down, that's fine. As long as the new water is near the same temp and PH, you can't really do too many water changes.

Don't add anymore fish until you have 0 ammonia and 0 nitrite for a few days in a row without water changes, even then only add 1-3 at a time several weeks apart and you should still monitor your water with new additions in case you need to do extra water changes to keep things in check. I'd also suggest posting here again once you're sure your water conditions are ok with what fish you currently have and what you'd like to add to make sure there are no compatibility or overstocking issues to consider before adding them.

Good luck to ya! Glad you found Aquaria Central

 

[ooooooooo]

Tetras aren't very hardy fish and can die easily from ammonia and nitrite being too high. This would be my first guess anyway as to what is happening.

Nitrite test kit is on its way. Haven't needed one for a while!

How did you acclimate the new fish to your tank?

I left the new fish in their bags to adjust the temperature, then added water to them from the tank over half an hour, until it was about half and half. Fed the other fish and switched the light off, then added the new fish properly. No quarantine facilities of course... All was okay for the first two days.

With NTD, there is a significant loss of color to the fish prior to death, so unless you saw those symptoms, I would doubt that was a cause.

I've just discovered a missing tetra alive. It is having trouble with equilibrium, colour is OK, being bullied by the zebras. I've put it in a bag in the tank to avoid it being molested and monitor it a little. It is sort of losing its colour a little. I agree though, it doesn't really sound like Plistophora given what I've just read about it.

If you are unfamiliar with the cycle process...

I'm aware of the cycle, don't worry. I'm probably just complacent as I've had the tank for so long with no problems. In the end I've added six very small fish and a shrimp, which I would have thought was a small extra load. But I do agree that it is a possible cause along with all the others. I'm doing a 15% water change now just in case, and will do more if the nitrites turn out to be high. I did a smaller change just before adding the new fish.

Another problem you will have is the clown loaches will grow very large, too large for an 18 gallon tank. They get to about 12" long.

I've only recently found out that the clown loaches get very big I was told they "grow to the size of the tank" (!) i.e. won't grow so big they are uncomfortable. I'm planning on getting a bigger tank soon. The biggest loach is currently 10cm/4" (about 5 years old - part of the family). To be honest I'd love a huge tank but can't carry it up four flights of stairs!

Will report back on progress. Thanks all for the quality advice, I hope one day I can reciprocate.

Cheers,
Ben.

 

[ooooooooo]

Nitrite levels normal

Nitrite level is undetectably low on the kit I'm using - nitrite ions < 0.3mg/l.

The poorly tetra has died, one remaining now.

If it was a nitrite spike, it was very short-lived and everything is back to normal. Will test again in the morning. Given them some live food to perk them up a bit! All the other fish are fine.

Still a bit of a mystery in my book!

Ben.

 

[phanmc]

have you tested for nitrates? while less toxic than ammonia and nitrite, it will still kill fishes at high levels (over 40ppm).

 

[sdb]

And testing for ammonia would be a good idea, too.

 

[ooooooooo]

Remaining tetra has lasted the night in apparently good health.. I'll take a look at nitrate and ammonia test kits. These tests are very expensive, about £8/$15 each. I'll probably be able to justify it in terms of expense of fish and cruelty to animals... but I've never used anything other than nitrite tests, on advice of my local aquarium shop.

If the tetra lasts until the weekend I'll probably buy some more to keep him company, in which case I'll look at getting an ammonia kit too just to be sure.

Cheers,
Ben.