Why aren’t my fish growing

[Potato Patatto]

I think it’s hard to say what his water changes should be if we don’t know his nitrate levels and how fast they accumulate. So I would start testing those nitrates daily to get a baseline and do your wc’s accordingly. But I would agree that bio-load probably requires the reccomended changes. I only do two 30-40% WC’s a week and my nitrates don’t really creep above 10ppm, but then again I have a decently planted tank with anubia’s & swords and lesser stock. You have Pacus so that might not be a viable option.

I only say that cause I get the sense a lot of people here probably do a lot more WCs than they actually need. And the ones who actually need it probably aren’t doing enough but then again I’d say everyone here cares a little more than the typical hobbyist.

 

[FJB]

I only say that cause I get the sense a lot of people here probably do a lot more WCs than they actually need. And the ones who actually need it probably aren’t doing enough but then again I’d say everyone here cares a little more than the typical hobbyist.

I sincerely doubt this is the case. Ever!
Aquaria (even the largest ones) are but tiny boxes of water compared to rivers or streams, even small ones.

 

[Potato Patatto]

I sincerely doubt this is the case. Ever!
Aquaria (even the largest ones) are but tiny boxes of water compared to rivers or streams, even small ones.

I don’t think anyone can replicate Mother Nature, and if we wanna get deep these fish aren’t meant to be in tanks in the first place. And I understand the point of constantly new water. But I’m sure there’s a standard deviation graph somewhere that would illustrate a tail-off of benefits at a certain level of water changes. I bet changing 200% of the water in a tank weekly vs 400% weekly isn’t going to give you double the benefit. I bet it’s a very small benefit and at some point, isn’t worth the effort for x percent of that benefit. And some fish will require more WCs but at a certain point you probably just shouldn’t have a species of fish that requires a 90% WC daily because it obviously isn’t fit for a tank.

 

[Joshuakahan]

I sincerely doubt this is the case. Ever!
Aquaria (even the largest ones) are but tiny boxes of water compared to rivers or streams, even small ones.

He is right that we here at MFK care more than the typical hobbyists. For most as long as the fish are alive and eating, everything is good.

 

[eon aquatics]

how long did you have them for?
new fish might take a few days to start eating
try live food or vitamins
or you could try soaking the food in garlic and fish oil

 

[twentyleagues]

Clean water and a balanced diet are critical for growth. Tilapia is not balanced. Water change is going to be based on your needs, check your parameters to help decide. Most of this has been covered above.
While I think you can achieve near 0 nitrates without daily water changes via a few methods for extended periods of time, you need to remove other chemicals and replace vital water chemistry components more often. In a perfect world 100% water change daily would be best for our animals. It's not a perfect world and usually that 100% wc isn't feasible. Pay attention to the things you can control and control them.