Fish dying

[Adam Bewley]

Sorry if this has been posted already, or similar, just signed up so im a newbie!!!

I have a 60litre tank.

I have recently changed the water, but had 2 mollies die, then 2 platys.

Yesterday my third mollie died.

I now have 2 barbs, one has attacked the other and left her with half a tail. So I have put her in a separator tank to try and recover.

I would like to know if this has anything to do with the 2 'devil' black angel fish I put in there.

I did notice however after I separated the two barbs, that the dominant one then went after the red tail shark.

There is plenty of room in the tank, are there any suggestions as to what or why this has happened? Seriously thinking of giving up!!!

 

[FreshyFresh]

One of the biggest risks we take in this hobby is when we plunk new fish into a tank. Quarantining new fish is one option to greatly reduce the risk, but even with that, you're introducing something new into your nice sealed 'ecosystem' aquarium.

Are you monitoring your water parameters (ammonia, nitrite and nitrate). Do you do weekly water changes?

 

[CAPSLOCK]

What type of barbs? A lot of barbs are natural nippers (notably the popular tiger barbs), and this behavior is more problematic with small numbers. Having a school of barbs will allow them to pester each other and no one fish gets picked on too much. Then having no other barbs, your barb is now nipping the rainbow shark. These types of fish would be in large numbers in their natural setting, so this behavior is not a problem, but in a tank with only a few tankmates and no place to escape, it becomes an issue.

Are the barbs leaving the angels alone? Usually angels make good nipping targets because of their long fins, so keep an eye on that. If the angels are paired up and mating, they will try to ward other fish away from their chosen "nursery" area (in a small tank, this becomes driving all the other fish into corners as the angel pair claims nearly the entire tank).

If you haven't yet, definitely check the parameters - especially nitrite and ammonia - as the multiple losses at one time could well be a water quality issue. Or a loss can result in more losses - one fish dies and isn't noticed, and the ammonia spikes, then this spike kills the second, etc.