Why aren’t my fish growing

[PredatoryMonsterKeeper]

I have a 150 gallon with a gar a few catfishes Pacu and Oscar. I do weekly water changes and feed them tilapia daily. But for some reason I don’t see them grow

 

[Deadeye]

How long have you had them? Pacu and Oscar can put on over an inch per month. Same with gar if I’m correct.
How many fish in tank? How big of water changes? Likely the tank is overstocked and the nitrates are building up too high, stunting the fish. Also, full grown a 150 is not good for a pacu, they get 3 ft.

 

[PredatoryMonsterKeeper]

How long have you had them? Pacu and Oscar can put on over an inch per month. Same with gar if I’m correct.
How many fish in tank? How big of water changes? Likely the tank is overstocked and the nitrates are building up too high, stunting the fish. Also, full grown a 150 is not good for a pacu, they get 3 ft.

I’ve had them for about 6-7 months. I do about 40% water changes weekly. 1 gar 2 pacu 1 albino Oscar rtc shovelnose and a hybird rtc . I only notice the gar growing and I think I’m going to try and sell him or take it to my local fish store. Thank you !!

 

[tlindsey]

I've learned here that fish will release hormones that will inhibit fish growth.
Also having those species in a 150 gallon is a issue with only 40% of water being changed weekly. I suggest biweekly 50% wc's.

 

[PredatoryMonsterKeeper]

I've learned here that fish will release hormones that will inhibit fish growth.
Also having those species in a 150 gallon is a issue with only 40% of water being changed weekly. I suggest biweekly 50% wc's.

Thank you very much I will start doing that !

 

[tlindsey]

I have a 150 gallon with a gar a few catfishes Pacu and Oscar. I do weekly water changes and feed them tilapia daily. But for some reason I don’t see them grow

Get them on pellet's and rotate with the Tilapia.

 

[Jexnell]

I do fin level water changes every three days. And feed a staple of quality pellets with only one snack type food a week.

I started with this.

Six months

And a year later


I would say the best thing you can do to increase growth is water changes, followed by stress, then food.

Example two a group of Amphilophus Saggitae i got at the 2inch mark.

Six months later
Year mark

 

[BIG-G]

1 gar 2 pacu 1 albino Oscar rtc shovelnose and a hybird rtc

Am reading this correctly?
1 gar 2 pacu 1 Oscar 1 Red tail catfish 1 shovelnose catfish and 1 Hybrid Red tail cat.
In a 150?
What species is the gar?

I have no doubt that your nitrates are high that and the lack of adequate space is the issue with lack of growth.

What’s the long term plan here?

 

[esoxlucius]

It's well documented that long term exposure to high levels of nitrate can inhibit/stunt growth, not to mention cause a plethora of other issues.

Thin out your stock and whatever's left put a water change schedule in place to ensure your nitrate dosen't rise much above 20ppm with the remaining fish.

And by thinning out your stock, i'll be completely brutal here, offload everything except your oscar. Many of those fish shouldn't even be mentioned in the same sentence as '150g tank', never mind kept in one.

 

[duanes]

I agree with the others, with that stock (even with juvie fish), you should be doing "at minimum" 40% water changes per day.
Then you will get growth, but then the problem becomes, that only the oscar is fit for a 150 gal tank.
In nature Pacu are primarily vegetarian, so Tilapia (although reasonable for the other fish), is not that great for the Pacu.
A friend has 3 adult Pacu in a 10,000 gal tank that are about the size of garbage can covers, with some oscars and 4 ft red tail cats, and feeds the Pacu separately with bananas, other fruit, and vegetation type foods.
The pacu and cats as adults will need at least 1,000-2000 gallon tanks, and will still need daily water changes.