Crenicichla proteus Cope 1872

Crenicichla is the largest family of cichlids in South America, with more that 75 described species. There are also discovered a large number of species which are still not described. Also known as pike cichlids, these fish have an undeserved reputation for greediness and bad behavior among fish keeping people. With this article we will try to shed some light on the positive and very interesting sides of these fish. Crenicichla proteus belongs to the Saxatilis group, which is the largest group counting 28 described species. Representatives from this group are found in almost all river systems where Crenicichlas are found. The Saxatilis group species all have the same body shape and the characteristic black shoulder spot and reaches a length of 20 cm, ready to spawn already at 12 cm. These species belong to the most popular Crenicichlas, due to modest demands on water quality and tank interior. They are also the most frequently available in stores.

C. proteus has, as other Crenicichlas, a long, slender body, tapered towards both ends from the middle of the belly. The body is grayish white, with a black sideline from the head to the caudal peduncle. The species has a noticeable dark spot just behind the gill cover, as well as a smaller spot on the caudal peduncle. Seven dark bands runs from the dorsal fin down to the sideline, and two more bands runs across the head in front of the dorsal. Proteus has a relatively large, pike-like mouth with yellow jaws, and partly red eyes with a smaller reddish brown triangle below the eye. The pectoral fins are yellow tinted, otherwise all fins are colorless except for the upper half of the dorsal which is red tinted with a black trim. The female has a dorsal with white (lower) and black (upper, like male) trim, with one or more black spots with white (inner) and red (outer) edges. The female belly gets swollen and pinkish red when she is ready to spawn. Juveniles also have a black spot with an orange edge at the very end of the caudal fin, as well as 15-20 thin shining bands on the body sides.

Orosa river tributaire, collecting site. Photo by Erik Wolla.

C. proteus is found in the region of Loreto in northeasterly Peru, in the upper part of what is otherwise known as the Amazon. Here the species are found in most biotopes in the tropical rain forest, both in white, clear and black water, among others Napo, upper Putomayo and Ucayali, Pachitea, Aguaytía and Callari. On the extreme, the water temperature varies between 17 and 28 degrees centigrade, but normally lies between 25 and 27 degrees. The pH varies between 4.5 and 8.2, normally between 6 and 7. The large variations are for the most part caused by an increase in the inflow of water due to heavy rainfalls in the elevated regions up towards the Andes.

The specimens we had access to was collected by Erik Wolla in July 1996 in white water biotopes both in the lower parts of Rio Orosa as well as at the village of Yanashi in the Rio Solimões (Rio Amazonas) itself. Both locations being around one day travel by boat northeast of Iquitos. The collecting spots at Rio Orosa were from the mouth to a few tens of meters up small tributary creeks, typically with sunken logs, branches and leaf-litter on the bottom. At Yanashi there was little sunken wood material, however a few plant species were found, among them the floating plant Pistia stratiotes. At both collecting areas the pH was ranging from 6 to 7, and the temperature from 25 to 27 degrees centigrade. A total of 17-18 specimens were collected, but 2-3 was discarded as they were too big and hence would have taken to much space during transportation back. Further 2-3 died the last few days before the return trip, so a total of 11 made it alive back to Norway. These were quite small, between 3 and 6 cm. (TL).

Yanashi collecting site. Photo by Erik Wolla.

Fish caught by Saul at the city of Santa Cecilia in 1975 had fish, fish eggs, insects, shrimps and snails in its belly. This varied diet suggests that Crenicichla proteus should be straightforward to feed in captivity. A shrimp mix with peas, cod and miscellaneous vitamins works fine. They are also fed from time to time with live small fish in order to give them the opportunity to hunt for food naturally, something that is fascinating to witness. Crenicichla proteus shows no interest for flake food, tetra sticks or the like.

At Erik Wolla's these fishes were kept in a 160-liter tank with roots and flat rocks arranged to provide lots of hiding spots. During the first weeks two died by simply jumping out of the tank as approximately one-fifth of the tank cover was slid away. Somewhat later, one of the biggest fishes was found dead, the cause not clear. A massive water change was done. Somewhat later, in October 1996, a spawning pair consisting of the largest male and a large female separated from the rest. These two had staked out one end of the tank as their territory and spawned underneath a rock slate there, keeping the remaining inhabitants squeezed up against a corner at the opposite end of the tank. None of the others were killed or injured, though. They were moved to another tank to give the spawning pair less distraction. The eggs after the first spawn disappeared after two days, but the pair spawned again a few weeks later.

The fry became free swimming after 5-6 days and started eating brine shrimp naupli immediately. For quite some time after entering the free swimming stage, the female put the fry "to bed" at night. Heavily fed with brine naupli, the fry grew quite fast, and reached a length of 2-3 cm. after just 5-6 weeks. At this size, the fry also started to feed on "adult" food.

Crenicichla proteus fry. Photo by Per Øivind Pettersen.

After a heavy water change a couple of weeks later, the male started to chase the female to the point that she was stressed to death. The male was moved to the tank with the six other proteus in a 720-liter tank. One of these was a female clearly in the mood for spawning, and quite soon it looked like these two were a potential couple. In this tank the 7 Crenicichlas were kept with other similarly sized cichlids as well as corydoras and suckermouths for several weeks without problems. The couple was later moved to an empty 160-liter tank where they spawned. This batch of fry also survived.

At Per Øivind Pettersen's the fish spawned in a 250 liter tank at a temperature of 25 degrees , pH at 7.0, dH at 6-7 and kH at 2. The couple dug a cave underneath a big root, and deposited 300-400 eggs underneath the roof of the cave. The eggs were oval, light yellow and approx. 3 mm long. As with most cichlids, the female guards the eggs while the male patrols the outer rim of the territory. He displays a dark horizontal line as well as vertical bands when he chases intruders. The territory is guarded quite intensely, so one ought to be careful when poking fingers around. The eggs hatched after 2-3 days, after which the larvae remain hanging from the roof for one more day. The female moves the fry around to different pits in the gravel and on the roots until they become free swimming. One night a Panaque suckermouth ate all the fry, and the male responded to this by chasing the female around such that she was stressed to death. Probably he was ready to spawn again and did not get any response from the female. He had previously shown no aggression towards the female. As experienced by Erik Wolla, heavy water changes may also set the male in a spawning mode, with catastrophic results for the female if she is not ready.

This species has a moderate temper for being a Crenicichla. Only under special circumstances where the male is in spawning mode with no response from the female, aggression with loss of fish as the consequence may occur. As with so many other cichlid species, it is only aggressive towards other members of its own species. Other fish are left alone unless they enter their territory or are small enough to be regarded as food. For adult specimens, this would be free swimming fish less that 5 cm. Catfish, in particular corydoras, seems to be quite safe even if they are smaller than this. With this article we hope we have stirred your sense of curiosity for these fascinating cichlids. Crenicichla proteus is a good starting point for getting to know these fish.

References

• Kullander, Sven O, 1986, "Cichlids of the Amazon River Drainage of Peru", Swedish Museum of Natural History, Stockholm.