Malawi Eyebiter, Dimidiochromis compressiceps

Working as I do in marketing, I can see the sales potential in giving a fish a good name. The Malawi eyebiter has just such a name, attracting those who like to keep predatory fish while at the same time creeping-out those types of fishkeepers who don’t. 

The Malawi eyebiter, Dimidiochromis compressiceps, was given its common name in 1966, when Wickler found fish eyes in the stomach contents of wild caught fish. In his book “Malawi Cichlids in their natural habitat”, cichlid guru Ad Konings references this event, while at the same time stating that such eye eating behaviour had never been observed in the lake – and he should know. 

So the eye-biting behaviour that gave this cichlid its name went down as a bit of an anomaly, and certainly not the norm. I myself and other cichlid authors have also made that reference over the years and rejoiced in telling people that we, the informed, knew that they don’t actually eat eyes so not to worry that it would happen when keeping them in captivity. Until I kept them again recently that is!

Special delivery

So we wanted some fish to fill up and test out a commercial filtration system at my work, and along with the stunning Thorichthys maculipinnis that I went on to keep and breed, my mate Mark McKinney at Clearly Aquatics came over with several adult pairs of D.compressiceps. He opened the lid of the oversized bucket as I peered over and exclaimed at the size. They were fully grown – the males a good seven inches in length, mature, and in colour. And there were plenty of females too. From above I could see their shape in more detail. They are very laterally compressed as their name suggests, but what you don’t usually see is that these fish are tapered both at the back and the front too, making them Javelin-like in top profile, perfect for lunging at prey. Not prepared for their size, they were split into two systemised aquariums, one three feet long and one four feet. 

The fish fed well on Whitebait, cockles, mussels, cichlid pellets and even koi pellets. When gorging themselves on the large, thawed-out Whitebait I could observe just how large and protrusible their mouths actually were. I wouldn’t trust a hungry compressiceps with any fish half its size or smaller…

Wife beaters

But with condition came the inevitable fighting, as the dominant male in each tank took a large territory by force, banishing all males and from females from it, inviting females by invitation only, and then expanding the no swim zone to the entire length of each tank to other males. With nowhere to go the inferior males got bitten over and over again until it was time to intervene. Even the females got fed-up and formed a hierarchy, with the smallest female getting snapped at and bitten, and even not allowed to feed, which made them smaller, and darker in colour, and even more of a target to the others. I removed one casualty, looking as beaten up cichlids do, like it had been rubbed up and down a cheese grater. It was also missing an eye…

The one luxury I did have however, with commercial fish tank racking, was other tanks, albeit small tanks. I reluctantly went against my own advice and removed the aggressor instead of the victim. Within hours, after the resident raging bull had been removed, the next male had stepped up to the plate, taking his territory, and continuing the onslaught of aggression. This time I removed the victim, the worst looking female, followed over successive days by beaten up male, then beaten up female, until I had about 10 tanks with one fish in each, five males and five females. 

Divided only by glass, the males now all became masters of their box shaped worlds, colouring up and displaying to each other and the females, which were in sight and smelling distance. Away from harm the males became superb specimens, refracting both blues and green colours all over their bodies, with fire coloured crests on their dorsal fins, mirrored on the anal fins, and with lots and lots of dummy egg spots. 

As tanks needed to be given over to successive batches of the Thorichthys, I decided to reacquaint the five females with each other in the four footer, this time decorating the tank with lots of rocks, and strands of giant Vallisneria. This would usually be ok for virtually any Malawi cichlid, as females aren’t territorial or aggressive, and have nothing to fight over, but not so for the five female D.compressiceps. The largest fish became dominant over all, chasing the other four into the cover and not wanting them to feed. Like poorly discus the smallest female turned very black in colour and looked very sorry for itself. I made sure it could feed though, by feeding the others with so much Whitebait that they literally couldn’t eat any more. Once their mouths were full the last one would come out and get some food. Weekends came and went and one day I found I was now down to four females. The smallest, most beaten up female was again missing an eye.

This wasn’t what I wanted for these beautiful fish so I used my experience to set up a larger tank, this time a 5×2’, set up specially for them and decorated with a few rocks, lots of sandy areas and lots of now very long giant Vallisneria. I added the four females and the largest, most dominant male, adding him after the females had gone in. They looked great, gliding across the tank with great speed, while getting me thinking that they actually required even more room. An eight foot tank would have been ideal. 

I posted a picture of the tank to social media, but got heckled over my use of Vallisneria by one user. “Dimidiochromis compressiceps inhabit only rocks,” he stated, and there are no plants. I was pretty sure I had read every Konings book cover to cover, and even seen photographs of D.compressiceps over beds of Vallisneria. The user linked a YouTube video of a bright yellow compressiceps swimming over rocks around Chizumulu island. I quoted Konings where he said that Compressiceps were always associated with higher plants, apart from the yellow individuals at Chizumulu. But he wasn’t having it. Luckily Professor George Turner of Bangor University stepped in and confirmed that of all the compressiceps that he had collected from the lake, they had all come from beds of Vallisneria. My F1 fish may even be offspring of those that he has collected. My reputation intact I carried on enjoying the tank.

In the five foot tank the male would chase the females, but largely left them alone, building what would have been a circular bower in the sand if it had not been for the front wall of the tank. In true cichlid fashion he banked the sand up at the front to about six inches high, and over the next few days and weeks invited females over to spawn. But unusually no females were seen carrying either eggs or fry in the mouths, despite what should have been paradise for the one male and four females. I buffered the pH and hardness of the water, as soft acidic water can be a barrier for Malawi cichlids when it comes to breeding, but still nothing. Was the male too old I wondered, as he was a big, mature fish of unknown age. He certainly went through the motions but nothing came of it. So back he went to the stock tanks and this time I chose the smallest of the five, separated males. This fish was still large at six inches, but looked younger and had a smaller head and less developed features. Within days he had done the business and my females were carrying.

Compressiceps breed as all Haplochromine Malawi cichlids do. They are non-pair forming, maternal (female only,) mouthbrooders, with mating lasting only seconds. The male clears the area of other fish and shimmies and shakes, low to the ground in a circular motion. The female comes over, joins his circular dance before dropping a large, beige egg on the sand. She does an about-turn, picks it up in her mouth, before going to pick the next one up. Though this time he gets the quivering curtain of eggs that is the male’s anal fin, complete with a row or dummy eggs. This time she gets sperm, instead of eggs, and the process is repeated until she ends up with thirty or so now fertilized eggs in her mouth. Taking roughly a month from eggs to large, splittable fry, the female won’t feed during that time, and to the untrained eye doesn’t look out of the ordinary. It’s this mobile creche though that is key to the Lake Malawi cichlids adaptive radiation, something that Professor George Turner is world champion on. 

So what did I learn? That adults need large tanks, crowding works, but low numbers in small tanks don’t work, even with females. And that (in the case of mine,) they do eat eyes. There were no other fish present in the tanks when it happened, and one of mine lost an eye before it was killed. 

To the aquarium fish lover the males are stunning when in colour, and look expensive, if that’s at all possible. The females being silver, will just not be to the taste of most people although I still appreciate them, and they are essential for natural behaviour and of course breeding. The fry are large, easy to raise, and far more amiable to each other, even while being grown on in smaller tanks. If you don’t create a species tank, both males and females could be mixed in Malawi “Hap” tanks, with other, large predatory genera, although even then only one male Eyebiter will be best, and they won’t do well in the rough and tumble of the rocky, crowded mbuna tanks, accept when it comes to devouring fry. 

Dimidiochromis strigatus is also quite commonly available, with similar yet not quite so specialised body shape, more green colouration in males, and a large red patch behind the pectoral fin. These could be mistaken and even mis-sold as D.compressiceps, although once you have seen the real McCoy the difference is clear. Avoid hybrids, of which there are many. Orange Blotch “OB” compressiceps are 100% hybrids as they don’t occur in the wild. Albino fish look right in shape but again I wouldn’t trust them, and why would you want to handicap a perfectly adapted visual hunter with poor vision and a bright pink body? But if you are looking for the perfect cross of hard water biotope fish, oddball, and potential breeding project, and you have a large tank spare, I would give them a go.