View Full Version : Silver shark cats swimming up and down

04-05-2009, 10:56 AM
Hi guys,

Got 3 silver sharks and theyve been in the tank about 6 weeks. Added them altogether and they came out of the same shop, so havent seperated them.

Ever since ive got them, theyve been swimming in a circle in the bottom of the tank, staying together around the top then going to the bottom in a circle fashion, theyre bellies are showing at the front glass.

Occasionally, one does sit on the bottom and explores the rest of the tank, but other than that, this is the way they behave.

Have 2 pictus catfish, and they are ok at the other side of the tank.

Is this a sign of stress?? Or something worse?? Bit worried about this as they are beautiful fish and really want them to flourish.

Any ideas??


04-05-2009, 10:59 AM
what species are the catfish, Kai? I have suspicions, but will wait to hear from you on the species name. How large is your tank, by the way?


04-05-2009, 11:05 AM
Hi Dave,

Silver tipped, and they are in the 80 gallon tank, till the 100G is cycled.


04-05-2009, 11:10 AM
Hexanematichthys seemanni, then. You do know they are a brackish water fish that gets more than two feet long, right?


04-05-2009, 11:18 AM
yep, My dad kept catfish for 15 years and am well read up on them. The 100G is just for the cats, nothing else, and will be conditioned for their species alone.

I think its just stress, the 80G is not crowded, but its not really suited to the optimal conditions for the cats.

04-05-2009, 12:25 PM

Update on this one.....

Done a full test on the water, its hard water, but has a low level of salt and a ph of 7.0.

What Im going to do is add aquarium salts to raise the PH to 7.5 which after looking at the rest of the community, is still acceptable, and the salt to create brackish water Im taking a best guess that it will be ok as itll not change the water chemistry too much for any adverse reactions.

Any opinions on this one??



04-06-2009, 12:59 AM
Well for one thing you need to add sea salt not aquarium salt.

04-06-2009, 08:19 AM
So why in the hell are the local aquarium specialist telling me different!!! yee Gods!!!

Anyyways, how will freshwater fish react to saltwater exactly?



04-06-2009, 08:30 AM

They only do this during the daytime, during the night, normal behavour occurs.

So I assume that this is stress during "Peak Time" Any takers on this one??

04-06-2009, 02:53 PM
Are they Cetopsis Coecutiens, also called blue shark cats?

Do they have tiny little beady eyes and hardly visible barbels?

If so the swimming in circles thing is just what they do, ALL OF THEM.

For the rest of their lives.

Well... when they aren't biting chunks out of your other fish that is. lol

I'd take them back.

They also get big.

04-06-2009, 02:54 PM
Oh I didn't see you confirmed the species name inthe other post.

That sounded like blue shark cat behavior.

I'm glad you don't have those. haha

04-07-2009, 09:07 AM
yeah so am I , although I did have th echoise of having those, and actualyl was told by the pet guy that they are ok to keep as a community!!! Its just lucky that I know enough about catfish to know this!!!!

Anyways, any light on this behavour??

Thanks all


04-07-2009, 01:28 PM
Blue sharks as a community fish?? Noooooo!!! hahaha

You made the right choice.