inferior quality petricola w/ fin problems

[RoseFishWatcher]

Short version:

What might cause petricola to develop small/missing fins? Genetics or improper water when young?


Long version:

Hello! I'm a long-time lurker and check this site nearly everyday

Catfish are the best! So when my favorite lfs started carrying Syno Petricola, it didn't take much to convince me I should get a few. They were bred locally by two different people, both of whom the store gets them from.

I started with 4 in a 10g tank, as they were pretty small. Later, they we're moved into a 20g long, their current home. After moving them to the 20, I got 2 more for 6 total.

All of them are happily, active, and have grown. They are easily one of my favorite purchases.

However, 3 of the first 4 I got (all siblings I'm sure - the store kept fish from the 2 different breeders in separate tanks) have finage problems. They are either missing or have very very tiny pelvic fins. The fish swim normally, and have been healthy since I got them - I've had them awhile, although I can't remember when I bought them.

As I said, I love these fish. However, I was wondering at the cause of the abnormal fins. My initial assumption was that they were inbred. However, lately I've wondered if water quality (either pH, cleanliness, or some other factor) could have caused them to develop incorrectly.

Any thoughts?

[toddnbecka]

I received a shipment of 10 petricola some time ago (over a year). One I call "Lefty", because it is missing the right pectoral fin. It also appears to have an abnormal eye on the left side, though it doesn't act any differently than the rest. I had wondered whether the missing fin may have been lost to another fish, since the older fry are known to eat smaller fry. That wouldn't account for abnormal fins though.
I learned from sad experience how overcrowding and insufficient water changes can cause cichlid fry to develop badly, but I didn't see missing or abnormally developed fins among them.

[Marc van Arc]

What might cause petricola to develop small/missing fins? Genetics or improper water when young?
Any thoughts?

I would say genetics rather than poor water quality. It's true that fishes that have lived too long in poor conditions will not develop as they should have, but this mainly concerns older fishes. Although I must say that most of these - provided they get good care - tend to get and look better after a while.
The fact that your fish were young when you bought them indicates (imo) that these must have been inbreds. Fishes don't "loose" fins because of improper water.
I had the same overhere with (which turned out to be Czech-made) Cory sterbai: small pectoral spines and fins, bad eyes, torn fins etc. Although they're kept well the above mentioned features don't heal...
The solution is simple but hard: see to it that these don't breed and add some other specimen from another source.