Kribensis - Pelvicachromis pulcher

[AJ356]

I have a group of about 28. They were born in my care in August 2024. So, they are 13/14 months old. I reckon something along the lines of about 8 males in the group and the rest female, which makes sense as my pH is about 7.6 to 7.8

My QUESTION is their size.

Obviously, fish within the same broods grow at different rates. However, these fish are now a year old. About 33% of them are thick bodied (especially the females as you know) and about 2 inch big (and I have a few males at about 3 inch), then about 33% of them are a bit slimmer and about 1.5" and then the other 33% of them are about 1 inch and really slim.

I mean....... 13 or 14 months old and 1 inch for a Kribensis???

I'm planning to rehome some of this group now. Do you think once the smaller ones are out of this dynamic, their growth might increase (in theory?). Obviously, there can only be room for so many alpha males and alpha females in the group at once.

It's just that if I am rehoming some, it will include some of the very small ones and I want to be fair to the next person. Do you think mine might be permanently stunted, or could this be normal for one year in, with a large cichlid brood growing up together? They have not had the biggest tank, 3 1/2 feet long. The water changes have averaged about 40-50% every 10 days. I believe their diet has been good, but that can be clarified if you need me to. In the last 6 months, they have only been fed once a day, and so I know that might be a factor in them not having great growth thus far.

 

[gwand]

One factor for their small size is the large number of fish given your relatively small tank size. Overcrowding stunts growth.

 

[AJ356]

This is quite interesting. I think the author used to post on this forum many years ago https://www.practicalfishkeeping.co.uk/features/do-hormones-restrict-the-growth-of-fish/

 

[Colin_T]

Probably dominant males bullying smaller males and stopping them from growing and lack of food.

The fish should be close to full size within 6 months and certainly by 12 months. If fish are stunted it's generally from lack of food or lack of water changes or a really small growing environment, but even in a small tank fish can grow quickly if you do lots of big water changes and feed them well.

I used to grow rainbowfish and Apistogramma dwarf cichlids in 2 foot tanks and they were 2-3 inches in 3-4 months. They got fed 3-5 times a day and got a range of foods including marine mix, frozen bloodworms, microworms, baby brineshrimp and flake food. The tanks got a 75-90% water change each day and had an air operated sponge filter in them. The fish grew pretty quickly in those conditions.

Water temperature can also slow the growth of fish and most tropical fishes grow faster at temperatures around 26-28C

 

[AJ356]

Probably dominant males bullying smaller males and stopping them from growing and lack of food.

The fish should be close to full size within 6 months and certainly by 12 months. If fish are stunted it's generally from lack of food or lack of water changes or a really small growing environment, but even in a small tank fish can grow quickly if you do lots of big water changes and feed them well.

I used to grow rainbowfish and Apistogramma dwarf cichlids in 2 foot tanks and they were 2-3 inches in 3-4 months. They got fed 3-5 times a day and got a range of foods including marine mix, frozen bloodworms, microworms, baby brineshrimp and flake food. The tanks got a 75-90% water change each day and had an air operated sponge filter in them. The fish grew pretty quickly in those conditions.

Water temperature can also slow the growth of fish and most tropical fishes grow faster at temperatures around 26-28C

Thanks Colin, some really interesting points there, especially about temperature.

 

[GaryE]

What I take away after years of growing P kribensis and pulcher (the hobby krib) is the water changes. It's a small tank and if you want to grow them, reduce hormones and pollutants in the water. They should grow fast.
I never had time to do daily water changes, but with young Cichlids I want quick growth from (or now that I want growth from) regular water change routines aren't enough. I would do 40% every second day. If I were growing them for market now, I'd do daily, now that I'm retired.

 

[gwand]

What I take away after years of growing P kribensis and pulcher (the hobby krib) is the water changes. It's a small tank and if you want to grow them, reduce hormones and pollutants in the water. They should grow fast.
I never had time to do daily water changes, but with young Cichlids I want quick growth from (or now that I want growth from) regular water change routines aren't enough. I would do 40% every second day. If I were growing them for market now, I'd do daily, now that I'm retired.

Is stunted growth in these situations accompanied by a shortened life expectancy?

 

[GaryE]

Chicken or egg, @gwand . Most stunted fish end up culled, or not equally cared for. That's not physiological, but they do tend to have shorter lives.

In the balanced aquarium era, my stunted variatus often seemed to live long, but the conditions that stunted them also probably killed them.

 

[Back in the fold]

If fish are stunted it's generally from lack of food or lack of water changes or a really small growing environment, but even in a small tank fish can grow quickly if you do lots of big water changes and feed them well.

This is my problem with some Nothobranchius guentherii fry I’m raising . For want of a larger grow out aquarium approximately 50 fry are in a ten gallon . I feed them copiously twice a day and I also do a fifty percent daily water change . I don’t dare miss a day because I can smell the ammonia in the water if I even go a couple hours late . So far so good but I really need to off some of them to my local pet shop and keep the nicest ones for my next generation .

 

[GaryE]

Right now, I'm breeding a fish not unlike Pelvicachromis pulcher - Parananochromis brevirostris. It's from a couple of thousand KM south of pulcher, but is similar to keep, although way more demanding and kind of difficult.
In order to assure myself of pairs of this slow to sex out fish with uneven sex ratios, I currently have them in the 20 gallon they spawned in, and then in 4 other 20s, 2 40s and a 75.
It sound excessive and probably nuts, but if you want to breed quality dwarf Cichlids, you need quality rearing space. Because brevirostis has its sex ratio issue, I think I'll be fortunate if I get 5 pairs out of the 100 or so young I have here.
Then harsh reality kicks in. No one wants or can afford to ship in the pairs that I can't keep (I'd like to have 2 to 3 pairs total). No one wants the surplus males. I have to put them in a 75, where they will gradually kill each other. The survivors become an insurance policy/reservoir against losses.
It's not a popular fish. Your pulcher is, but you should aim to move them out asap. If you have a local store, sell all the quick growing, normal sized juveniles. Then see if the stunted ones will go on a growth spurt with clean water. If they won't, it's unethical to sell them to someone who expects them to become regular sized adults.
If they don't 'take off', then you either have an overcrowded tank with eternal water changing and no natural type behaviour, or you face culling - euthanizing the fish that you can't keep. It's not a nice side of fish breeding, and in time breeders will reduce brood sizes at the outset (feeders for other tanks) to avoid having the species crash from overpopulation, or they'll do what I did here - get more tanks. I see no choice in between. I wish there were millions more hobbyists clamouring to take in huge numbers of these great little fish, but dwarf Cichlids are in style now.