Fish not growing. Why

[Hybridfish7]

I have a pair of 1" sajica that have been an inch for almost a year now. They are in a 40 and receive 2 70% wcs a month. I try to feed at least once a day, but will usually throw food at them anytime I'm in the fishroom in hopes of getting them to grow. Nitrates are miraculously low, around the 10 ppm range.

I additionally have a group of platinum honduran red points, of the same size, in a 20, who have not grown since I got them July last year. Same story.

My pair of F1 myrnae in my 33 long has also not grown over the last year. Actually the male doubled in size and stopped at 2.5". Female stopped at an inch. They have not bred.

Temps of all of these tanks are in the low 80s, around 81-83F.

Meanwhile I have normal colored honduran red points (some from the same source, being Rusty Wessel himself) in an unheated tank, who have doubled or tripled in size since I got them. Not as fast as I'd expect, which I understand and somewhat take as a blessing, as their tank is unheated, so I take it as a healthy rate of growth for them. I have domestic strain convicts in a 20 and 29 who grow pretty steadily, my largest being 4-4.5". I have lago nicaragua convicts in a 10 gallon who are also growing. My septemfasciata fry also grow at a pretty rapid rate in their 40.

Why?

 

[neutrino]

At first read the difference appears to be temperature. Water changes same for all tanks?

 

[duanes]

I have a pair of 1" sajica that have been an inch for almost a year now. They are in a 40 and receive 2 70% wcs a month. I try to feed at least once a day, but will usually throw food at them anytime I'm in the fishroom in hopes of getting them to grow. Nitrates are miraculously low, around the 10 ppm range.

I additionally have a group of platinum honduran red points, of the same size, in a 20, who have not grown since I got them July last year. Same story.

My pair of F1 myrnae in my 33 long has also not grown over the last year. Actually the male doubled in size and stopped at 2.5". Female stopped at an inch. They have not bred.


Why?

For certain cichlids, water changes are more important than others.
It depends on how pristine the waters are, where they evolved
When I test natural water here in Panama, I never find any detectable nitrates.
To me, two 70% water changes per month are very wimpy.
My male sajica easily hit 8" in a year, but I normally do a 30-40% water changes every other day, so it turns out to be often over 100% per week, and n much larger tanks.
Growth inhibiting hormones and nitrates tend to build up quicker in smaller tanks.
And my myrnae male also hit about 6" with that water change routine.

Both these pairs have each spawned a number of times. Below river water tests for nitrate, and pH, here in Panama.

I check every river for these parameters I collect in, and have yet, to get detectable nitrate.....very telling...

 

[Hybridfish7]

At first read the difference appears to be temperature. Water changes same for all tanks?

Yes

 

[Iwhoopedbatman]

OP said his nitrates are around 10 ppm. It's not his WC schedule. Hormone build up wouldn't cause this at this extreme level either. 2 1 inch Sajicas are not overflowing a 40 gallon in anti-growth hormones with that WC schedule. Something else is going on. I'd question your source water. It could also be bad genetics, possibly internal parasites. I really have no idea, but I don't think just saying 2 70% WC/month is insufficient is getting you on the right path here. Many decades ago when we didn't know everything we do now and the internet didn't exist, most fishkeepers didn't do close to 2 70% WCs in a month and our fish still grew.

 

[Hybridfish7]

OP said his nitrates are around 10 ppm. It's not his WC schedule. Hormone build up wouldn't cause this at this extreme level either. 2 1 inch Sajicas are not overflowing a 40 gallon in anti-growth hormones with that WC schedule. Something else is going on. I'd question your source water. It could also be bad genetics, possibly internal parasites. I really have no idea, but I don't think just saying 2 70% WC/month is insufficient is getting you on the right path here. Many decades ago when we didn't know everything we do now and the internet didn't exist, most fishkeepers didn't do close to 2 70% WCs in a month and our fish still grew.

It's really weird, because like I said I do still have fish that grow, some even being of the same species and from the same source (siblings). I have a friend who keeps his sajica in the same conditions, the sajica themselves being from the same source, and they grew. I had a problem with my Rio bagaces nigrofasciata fry not growing last year, but the ones I sent to a guy in Texas shot up to 4.5" in a matter of months. That's when I started questioning my water, but things just don't add up. I had another pair of myrnae in a 29 that only started growing once I put them in my dad's 55, and he does even less waterchanges than me. His nitrates were in the red, and his male myrnae got to about 5" before he brought them down. The fish themselves don't look or act unhealthy. They just don't grow

 

[Iwhoopedbatman]

It's really weird, because like I said I do still have fish that grow, some even being of the same species and from the same source (siblings). I have a friend who keeps his sajica in the same conditions, the sajica themselves being from the same source, and they grew. I had a problem with my Rio bagaces nigrofasciata fry not growing last year, but the ones I sent to a guy in Texas shot up to 4.5" in a matter of months. That's when I started questioning my water, but things just don't add up. I had another pair of myrnae in a 29 that only started growing once I put them in my dad's 55, and he does even less waterchanges than me. His nitrates were in the red, and his male myrnae got to about 5" before he brought them down. The fish themselves don't look or act unhealthy. They just don't grow

Honestly, I'm at a loss. While I don't think it will hurt at all to up your WC schedule, and would suggest trying it if there's nothing else you can think of, I'd be shocked if that turns out to be all it is.

 

[Hybridfish7]

Honestly, I'm at a loss. While I don't think it will hurt at all to up your WC schedule, and would suggest trying it if there's nothing else you can think of, I'd be shocked if that turns out to be all it is.

As much as I love sajica I'm honestly on the verge of just selling that pair and moving my dimerus to that tank

 

[Iwhoopedbatman]

As much as I love sajica I'm honestly on the verge of just selling that pair and moving my dimerus to that tank

From your fish list, it sounds like you like the cryptoheros/amatitlania families the way I love my acaras. Sorry you're having trouble with them.

 

[Hybridfish7]

From your fish list, it sounds like you like the cryptoheros/amatitlania families the way I love my acaras. Sorry you're having trouble with them.

It happens, and I love my acaras too, just not as much as the convicts. I have paso de la cruz dimerus and an esmeraldas gold amazonarum, amazonarum is what started all of this though