Mysterious Molly Death

[inarnia]

This isn't really an emergency as the fish has died already, but I would really like to make sure it is nothing that can affect my other fish.

In the last 24 hours, my molly fell ill and died. When I woke up, he was laid on the bottom of the tank. When I encouraged him to swim, he had some difficulty getting off the bottom, eventually deteriorating into being unable to swim without spinning round and round. By the end, he did not even move when the other fish began to peck him.

There were no external signs of illness, so I immediately took my water for testing, and the shop said there were no pH or waste problems. I have four mollies and two platys in 60 litres that I have had set up for approx. 2 months. The tank (an Elite) uses the filter and heater that it came with and the filter output falls into the water oxygenating it. I feed once a day for approx. two minutes until they lose interest, and don't feed when I notice trailing poop on the fish. I gently rinse the filter in tank water twice a week and change 20% once a week. I add the tonic dose of standard aquarium salt at this time - but I am not sure if I ought to create a full brackish environment instead.

With the difficulty swimming, I thought of swim bladder, but I don't know if it is possible for a case of swim bladder to appear and kill within one day. Otherwise, I can't think of what could be wrong. I just hope it can't affect my other fish.

Any advice from more experience keepers (on any part of my regime) gladly appreciated.

 

[the_lock_man]

Sorry to hear of your loss.

Would I be right in assuming that when you set up the tank, you just ran the filter for a few days, and then put some fish in? I have an inkling that your filter is not yet mature enough to fully support the fish, and that may be what caused the molly to die. I am always suspicious when a fish shop says "yeah, that's fine", without actually giving you numbers. Many fish shop employees don't really know what's good and what's not because, for a lot of them, it's just their job - particularly so with the employees of large chains.

I would strongly suggest you invest in your own test kit, and it needs to be a liquid one, as the paper strips can often give false results. If not, have the shop test another sample, but get them to tell you the actual numbers in the result. Anything other than 0ppm for ammonia and nitrite is bad, whatever the fish shop employee may tell you.

To give you more detailed help, you need to post up your water statistics - levels of ammonia, nitrite, nitrate and pH.

 

[inarnia]

Thanks for your thoughts! Even after I do my research and think I have avoided the common mistakes, it still seems there a million things I am not doing right!

When I set up the tank, I bought live plants and floated food flakes in the tank in a net, replacing them every few days, and I left that set-up running through the filter for three weeks before adding fish. So I did not 'rush into it' as such but still I am sure you are right about the filter.

I think I will do as you say and invest in some proper testing for myself. It is an independent shop and they do advise you to be patient, start small, and test regularly, so I do trust them. But they do still only work in terms of "it's fine" so it would be good to know myself.

 

[the_lock_man]

The fish flake thing would have helped a little, it would have caused a small amount of bacteria to grow, but not nearly enough to support the fish.

Have a look through this link and this link.

The first is the background detail on what needs to happen in your filter, and the second is details of how you achieve this from the position you are in.

The other thing to say, is to forget the salt - these are freshwater fish.

 

[inarnia]

Thanks a lot for the links!

I have posted another thread in the general tropical fish forum on my salt issues. I read conflicting information on the internet regarding mollies and freshwater vs brackish environments and am very confused!

 

[the_lock_man]

Thanks a lot for the links!

I have posted another thread in the general tropical fish forum on my salt issues. I read conflicting information on the internet regarding mollies and freshwater vs brackish environments and am very confused!

Thing is, maybe the mollies would benefit, maybe not - but the platies definitely won't. Some fish are even less tolerant of salt, so you restrict yourself in what you can stock.