Hi,

The other night my red tail black shark died and just wanting to know if anyone has any advice why. I did do a 20 % water change 2 days before but all my other fish seem to be fine. I did notice the day before it died it was hanging around the top of the tank which it doesn't often do and its color had slightly faded. I purchased a Male Betta about 2 weeks ago and I noticed he was chasing the shark around quiet alot. Could it of been from stress because of that? any help would be great

Thanks

Makes a change, a red tailed shark being chased, they usually do the chasing LOL. Hanging around the surface is usually lack of oxygen... are any other fish coming to the surface for air? Have you checked ammonia, nitrite & nitrate? How many fish and what size is the tank?

More details are needed before being able to hazard a guess, like the answers to the questions snowman has asked.

Yeah all my other fish seem fine and I haven't noticed any other coming to the surface. I have a 120 litre tank with 1 Male betta, 3 kuhli loaches, 1 plec, 3 clown loaches , 1 dwarf gourami, 14 cardinal tetra's and 5 Cochu blue tetra's ( was 6 but 1 jumped out!) and 6 black neon tetra's. The Red tail shark seemed really friendly from what I have read about them. Rarely did it go any chasing. Just keeped to itself.

That's a lot of fish. I assume some will go into a larger tank as they grow? The plec and clowns will need larger accommodation.

Red tail sharks are usually very peaceful until they get to a certain size then they get aggressive. How aggressive depends on the fish.

Faded colour suggests stress but stress from water conditions or harrassment is hard to say at this point.

That is quite a few fish, have you checked nitrate (if its been setup for a while) & ammonia, nitrite (if its a newish tank).

Doing a 10% water change every couple of days for a week or so should tell you if its water conditions, if the shark is being chased a lot that could well be it, try putting the chaser in a breeding trap & see if that helps.