The African haplochromine from Lake Malawi known as Fossorochromis rostratus was first seen and recorded by Boulenger in 1898. It has been rather hard to come across until the past 15 years, this is because it requires a large tank with open areas as well as rocky retreats, and captive spawning is quite rare. In nature they live over sandy areas and forage in groups of females, subdominant males and small groups of Cyrtocara moorii, while the larger dominant males will create massive crater nests that are over a meter in diameter.
Before I get into my personal experience with the species, I will go through some of the stats, requirements and behaviours of the beautiful species.
First, they are a large fish, and therefore need their space to swim and grow. I would recommend a 70g tank as a minimum for fish up to 14cm (just under 6”), after that over 100g (350L) is a must if you are to have any success in keeping these fish. The substrate should be sand, medium grain sand is fine, just as long as it isn’t sharp, rostratus are known diggers and sand sifters, and course sand will scratch their faces and mouths. Also when threatened they can hide under the sand completely, and could do some serious damage. Large rocks for cover are good, though they are very much an open fish, they seem to enjoy swimming through gaps and crevices, and also it creates hiding spots for brooding females and beaten subdominant males (which is rare but can be quite bad). Only the robust plants can live with this species, not because they eat them, but because they dig up the roots, and can easily tear apart fragile plants, I would recommend vallisneria if you want some green in the tank.
In nature, as I mentioned before, the females live in groups with subdominant males, and the males will take up a territory and create large craters. This is not the case in captivity, if the tank is large enough, you will most likely see females hanging around together, but only in extremely large tanks, ponds or public aquariums will you see a male with a crater nest. They are obsessive at digging and sifting sand, they will constantly sift the sand for micro organisms and small crustaceans. Groups of 1-2 males with 3-5 females is recommended for fairly large tanks, having a second male will make the dominant male more intense, he will have competition for females and display better colors. The max size for this species is around 28cm (11”) for males and 22cm (9”) for females, in the wild though; males can reach up to 35cm (16”).
Their spawning habits are just the same as other haps, they are mouthbrooders, and the female will mouth brood the eggs for 23 or so days, before guarding the fry for an extra 2 weeks after releasing them. Spawns are large, up to 130 fry can be produced from a large female with experience. In captivity males attract females to a spot on the substrate or a rock, sometimes the females chooses the spot, they circle each other and the female releases up to 6 eggs at a time, she quickly turns around a picks them up. (Watching large haps spawn is very impressive in person, if you don’t get a chance; I have a 4.8 meg movie here.) Only mature males will spawn, it usually takes a male 2 and a half years to reach breeding size and maturity 20cm (8”).
My first experience with this species was a group of 3, one of which was male for sure; the other two remained in female colours. The group where about 13-15cm (5”-6”in) and lived quietly in my 70g aquarium, I didn’t know much about the species at the time and I sold them off to a keen friend who admired the male, I was quite happy seeing them once or twice a month, and they grew into full colours, the male reached about 20cm, and still growing, but he died when James (the friend) added in two females which introduced a disease, and the whole group died within a week of the new arrivals.
The second experience was 4 months of bliss, I was asked by a breeder to look after a batch of 50 and grow them to 5-6cm (2-2.5”in). I had a spare 4 foot tank and the little 1cm fry moved in with ease, they all had 4 or 5 little spots and moved around the tank like a silvery swarm of sardines. It was great; I became really keen on the species and obsessed with the idea of breeding them and having a constant supply of these cute little critters. Giving them back was hard, but I was given my payment for looking after them and offered some juveniles, I took the money (of course ) but I refused the juveniles and went searching for a slightly larger group, around the 10cm mark.
I came across a trio for sale, which had bred before, so I couldn’t refuse, even though I was looking for some younger ones. I picked them up and introduced them to my 6’ tank with no other occupants. The female was rather thin because she had just released a batch, they all looked healthy and happy, the male had vivid yellows, blacks, blues, golds and sometimes a bit of green and red, he was a stunning fish of 25cm (10”). There was a subdominant male that measured 23cm (9”) and the female was around 18cm (7.5”).