Oscar slow growth over an 8 months period

[Lucifer0411]

Hi all,

I have a mainly Central American tank with a couple south Americans including an Oscar. All are still juveniles (under a year old).
I've had the Oscar for 8-9 months. Although was fairly small when I got him is still only about 5 inches or so, but is quite solid and deep so well proportioned.
I've attached a photo, ignore the fact he is resting on the substrate, he just ate a big meal and the only chance to get a still photo of him, usually he is flying around the tank.

I expected an Oscar to grow quicker than that. Other inhabitants include silver dollars, salvini, green terror, red devil, JD, convicts, jaguars, vieja synspilum and a few ellioti along with a large sailfin pleco.
At the moment, none of the cichlids are bigger than a third to half their full size (apart from the Vieja).

Interestingly I added the green terror later, was fairly small but quickly grew to the size of the oscar then slowed right down. The Vieja, added the same time as the oscar has grown from about 3 to 8+ inches in that time. The silver dollars have grown quickly, the red devil, added only a few months ago has already doubled in size and is now around 6-7 inches.
The JD's and salvini added the same time as the oscar are are actually not as big.

No aggression at all in the tank though....well not yet anyways.

All I can think of is this particular oscars genetics or the fact he doesn't really take to dry food much. I've not long started increasing his frozen food like frozen fish etc. Will see how that goes over time. He is a very aggressive eater for food he likes but ignores the dry food etc. Favourite food is live food like earth worms or lumps of frozen food.

Oh, the tank is 10 ft (330 gallons) which he has been in since the start.

 

[tlindsey]

salvini, green terror, red devil, JD, convicts, jaguars, vieja synspilum

The Oscar may be lowest ranking.

No aggression at all in the tank though....well not yet anyways.

In the pic Oscars fins look nipped.

 

[Americancichlidsaredabest]

Are you sure there’s no aggression? Does the Oscar show any signs of stress? Hiding in the corner?

 

[duanes]

Sounds like a lot of fish in the tank, what size tank is it?
And all the cichlids would naturally be vying for alpha status, by producing growth inhibiting hormones..
What is you water change schedule per week, and how much is changed each time?
Usually when I see what I consider slow growth, the reason seems to be a lack of sufficient water changes to reduce growth inhibiting hormones, and not removing enough nitrate (also a growth inhibiting substance)..
The more cichlids in a tank, the more water changes, and larger volumes needs to be done.
On my tanks, I try to change at least 100% per week, by doing a 30% to 40% of the tanks volume every other day.

 

[Lucifer0411]

Sounds like a lot of fish in the tank, what size tank is it?
And all the cichlids would naturally be vying for alpha status, by producing growth inhibiting hormones..
What is you water change schedule per week, and how much is changed each time?
Usually when I see what I consider slow growth, the reason seems to be a lack of sufficient water changes to reduce growth inhibiting hormones, and not removing enough nitrate (also a growth inhibiting substance)..
The more cichlids in a tank, the more water changes, and larger volumes needs to be done.
On my tanks, I try to change at least 100% per week, by doing a 30% to 40% of the tanks volume every other day.

Hi thanks for your considered reply.
In answer to your questions, the tank is 10 ft long (330 gallons), I change 40% per week, have since the start, this is needed anyways to keep the nitrate levels relatively low. So that equates to about 120 gallons changed per week.

I think I have identified one problem (which in hindsight is my error) and that is not catering to his particular way of eating - which seems more fussy than all the other cichlids. So I've started adding frozen fish - basa fillets and some live earth worms etc and he is eating better now so it might just be a case of playing catch up with his diet.

 

[Lucifer0411]

Are you sure there’s no aggression? Does the Oscar show any signs of stress? Hiding in the corner?

Well when I say no aggression, I haven't seen any. Doesn't mean there isn't any of course. No he never hides, always front and centre.

 

[Lucifer0411]

The Oscar may be lowest ranking.
In the pic Oscars fins look nipped.

I mentioned there was no aggression but that's only because I have never seen any. Who knows there could be some going on. I can see the red devil will be the highest ranked if he isn't already. He is also growing the fastest and probably the one who would of challenged the oscar.

 

[duanes]

Hi thanks for your considered reply.
In answer to your questions, the tank is 10 ft long (330 gallons), I change 40% per week, have since the start, this is needed anyways to keep the nitrate levels relatively low. So that equates to about 120 gallons changed per week.

My system is also around 300 gallons, so I try to change at least, that 100% amount per week.