Shark Preparing For Cirque De Soleil (sp)

[subopposite]

Water is fine (weekly water changes 25%), no new tankmates, subject is a 5" bala shark, has been in the tank for over a year, no treatments added to water, except mela and pima fix when needed which is not often at all. Other tankmates are much smaller and placid and leave the shark alone...swordtails, tetras. Tank size is not an issue.
Basically this shark wouldn't eat for a couple of days and didn't swim around as much as normal, typically hanging out in the front corner of the tank, but not hiding behind anything. Now he does endless loop de loops in the water like he is on a non-stop rollercoaster. He will throw in some corkscrews too, but it seems his equilbrium is way out of whack and he cannot stabilize himself. There are no visible markings of sickness on him/her.
Anyone know what this is and if it can be fixed?

 

[DiscusKeeper403]

Seems like he has a case of whirling disease. This is a disease of the swim bladder, treat with Erythromycin. Bala sharks do best in groups of 5+ and they need a very large tank in case you didn't know.

 

[subopposite]

Thanks. While he is by himself, he is in a large tank. My profile is old and inaccurate. He is not in any of those tanks. Thanks again.

 

[WILDER]

Like to look at the size of tank in gallons or litres, how many fish and which type.
Water stats in ammonia,nitrite,nitrate,and ph.
Does it look like he's chasing his tail.
Any change in ph.