Oscar with mutated fin?

[Oceanica]

Hi guys, I'm new to this forum. Thought I'd ask for your opinion on something? I noticed yesterday that my oscar Totoro, which I've had for just over six weeks now, has a mutated anal fin. I don't know how I didn't notice it before! It looks completely right and normal *if* you don't know what it's supposed to look like, but it looks nothing like the anal fins of any other oscars I've seen photos of. Totoro is otherwise healthy, swims and behaves normally and eats like a pig. He's just over 5 inches now; he was just under 4 when I got him. I've attached a couple of pictures, one from when I first got him and the other taken today, so you can see that the fin looks exactly the same. There's no question of damage to the fin; it's structurally very different from what it should be. It's lobed rather than frilly, which makes me think Totoro is expressing an atavistic trait (genetic throwback) i.e. the fin looks like the anal fin of more primitive fish. Has any of you seen anything like it?

[JohnL]

Hi and welcome to the forum. With all the inbreeding that goes on with O's it's not surprising to have a fin abnormality. I have a tiger O that has this curly cue thing going on on it's dorsal fin. I think it just gives them character.

[OinKY]

Agree. It gives character.
Some genetic mutations show up in almost every O spawn. Left to their own devices they usually don't survive,but in the "mass produced" farming culture it's not unusual for them to survive,slip through the culling process,and make it to market.Unless major,fin deformities are not typically detrimental to quality of life for the O.
Same with injuries acquired when in the developmental early fry stages.

[donsfish]

Welcome to the forum. As long as the deformity doesn't cause problems for the fish......it's just a bit of extra character

[Gerry]

Welcome.
As stated this will be genetic and unlikely to alter over time.

[callen]

Welcome to the site!!
Agree with the others. With a healthy diet and clean water he/she should do fine.

[Oceanica]

Hi guys,

So, it's now early December and Totoro is only about 7 inches long including tail length. I reckon he should be nearly fully grown by now as he is about 10 months old; isn't he growing unusually slow? Ponyo II is in the same tank as him and is growing reasonably well; she arrived in September as a skinny 2" baby and has grown at least 2 inches since, and fattened up too, which suggests it's not the water or the food. They are in a 118g tank, 50% wc once a week, temp 25oC. Diet is mostly chopped mussel and prawns, with some good-quality pellet food as supplements. Totoro and Ponyo are fed twice a day. Totoro often rejects his food (he spits it out whole), which can't be helping this. Any thoughts, ideas? It would be sad if mighty Totoro, King of the Big Tank, turned out to be a midget Oscar.

[donsfish]

Just genetics again really and not something due to your care, considering we already figure on a bit of defect there not surprising that it's not growing as fast/large as most would. Also it's spitting the food out because it just doesn't need as much/as often as the new little guy. Once a day at this age would be plenty though I'd keep feeding more often as you are for the sake of the little dude. Just maybe try to target feed accordingly so there isn't as much food waste/spitting out going on that would lend to fouling the water faster.

[Gerry]

Just genetics again really and not something due to your care, considering we already figure on a bit of defect there not surprising that it's not growing as fast/large as most would.

Agree

Is he looking thin? if not he's just getting more than he needs. O's don't eat as much when the fast growing Juvie stage is past

[OinKY]

I'd chalk it up to his genetics too...
...but

Diet is mostly chopped mussel and prawns, with some good-quality pellet food as supplements.

Try reversing that.Totoro is past the stage where he needs mostly protein and needs a wider variety. If the pellets are mostly vegetable-based will help if he's super picky.
Ponyo II is still at a stage where the protein is spurring growth but you'd want to back that down too around March/April (6" at current rate) so probably better to get him use to a variety now too.

temp 25oC.

Try gradually upping that to 80F (26.6C).While it doesn't sound like much,3 degrees F may be just enough to speed metabolism where he'll eat better and accept more. No more than that and watch behavior as you do it.

Totoro and Ponyo are fed twice a day. Totoro often rejects his food (he spits it out whole), which can't be helping this

Totoro's at a stage where two feedings may/may not be what he wants or needs.Ponyo's at a stage where IMO it isn't enough.
In all honesty,an O isn't going to starve unless something's up so the two feedings probably work out if Ponyo is thoroughly cleaning up behind Totoro's rejects.

Upping temp slightly,wider variety on the food,and keeping nitrates low as possible (so test,then set water change routine) is all I've got as you can't "force" growth if it isn't there. The only possible issue might be accelerating Ponyo's growth which would make for more food competition that Totoro can't win...and a chunky,overweight,Ponyo.

[Oceanica]

Thanks for the advice everyone. Totoro does seem to like pleco wafers so perhaps it's because he's in need, as Oinky suggests, of a bit more plant-based food in his diet. Ponyo II does clean up his rejects pretty well. I have upped the temperature a bit, too. Wait and see, I guess!

[Gerry]

good luck

[Oceanica]

Totoro is still not eating much. He''ll eat the occasional pellet, but refuses the mussels and prawns he used to love. He has developed a rather unhealthy obsession with trying to eat the poor Giant Danios, who are very much stressed out. All very odd.

[jezzavw]

I love the look of your oscar he looks so cool

[OinKY]

He has developed a rather unhealthy obsession with trying to eat the poor Giant Danios, who are very much stressed out. All very odd.

Sorry being slow to comment on this.
If you upped the temp from something that an O is used to (as I suggested) this is the type behavior I was talking about watching for. If it isn't leading to aggression among the Os themselves then it'll be fine.