Amphilophus citrinellus (GÜNTHER, 1864)

Midas Cichlid

Classification

Order: Perciformes Family: Cichlidae

Distribution

Nicaragua and Costa Rica.

Habitat

Tends to inhabit large, permanent bodies of water including lakes and ponds, although it’s also been recorded in slow-moving parts of rivers. It particularly favours rocky walls and banks, where it forages among the crevices.

Maximum Standard Length

300 – 350 mm.

Aquarium SizeTop ↑

A tank with base measurements of 150 cm x 45 cm or equivalent should be the minimum size considered for a single specimen, but you’d need something larger for a pair or community containing other cichlids.

Maintenance

There are few fish that show less regard for a beautifully decorated tank than these. Don’t even consider a planted setup, as large quantities of the substrate will be shifted around on a daily basis. Rocks, driftwood and large flowerpots are all suitable provided they’re too heavy for the fish to move about, although it will undoubtedly try to do so anyway. You could try anchoring plastic plants down with rocks, but don’t expect them to stay that way for long. If there are other fish in the tank, arrange the decor to provide as many visual barriers as possible. Although unlikely to eradicate it completely, this will at least help to dissipate aggressive behaviour.

Similarly, any unprotected pieces of equipment such as heaters, filter inlets/outlets etc. will be attacked unless they are afforded some protection. Fit the strongest heater guard you can find, or conceal the heater and any other equipment behind immovable rocky structures, and use very strong suction cups on any pipework. The filter itself should be huge and efficient to deal with the masses of biological waste produced by this greedy, messy fish. Substantial weekly water changes are also a must, and the water should be high in dissolved oxygenation. Consider the use of a couple of big airstones to achieve the latter. A heavy cover is needed to prevent the fish leaping from the tank in one of its more excitable moments, of which there will be plenty!

Water Conditions

Temperature: 21 – 26 °C

pH: 6.0 – 8.0

Hardness: 90 – 447 ppm

Diet

One of the least fussy feeders you are likely to encounter in the hobby, most specimens will attempt to eat anything that looks as though it might be edible. Feed a good quality cichlid stick as staple, and supplement this with regular feeds of live and frozen foods such as earthworms, prawns (leave the shells on as they contain valuable carotene which helps maintain the orange/yellow colouration of the fish), mussels etc. Vegetable matter, including peas, spinach should also form a good proportion of the diet. High protein foods such as beefheart and other red meats are not a suitable option, as they can have a detrimental effect on the fishes digestive system. Similarly, while it does eat smaller fish in nature, there is little benefit in feeding live fish in the aquarium.

Behaviour and CompatibilityTop ↑

One of them most belligerent cichlids around, you need to know what you’re doing when attempting to keep a midas with anything else, and that includes its own kind. In very large tanks this aggression becomes less of a problem, but by very large we are talking in excess of 1000 litres, which is simply beyond the reach of most hobbyists. In tanks of this size it can be kept with other robust Central American cichlids, large Loricariids and other big catfish. Decent-sized fast swimming fish such as silver sharks, tinfoil barbs and the like are also a possibility.

Sexual Dimorphism

Mature males tend to be more well built than females, and develop longer dorsal and anal fins, and a more spectacular nuchal hump. These humps only develop during the breeding season in nature, but in aquaria many specimens possess enormous, permanent humps. In addition, the genital papilla is quite different between the sexes, with that of the male being thinner and more elongate than in the female.

Reproduction

Provided you can obtain a compatible pair, breeding is fairly straightforward. A tank of around 6′ in length is required, and this should be decorated with large rocks and flowerpots to act as potential spawning sites. It goes without saying that tankmates are not an option, as even if they are tolerated by the pair for a while, they will almost certainly be killed by the male when spawning commences.

Unfortunately, matching adult fish is a tricky process fraught with danger, with males often killing females if they are simply dropped into the tank together. Some hobbyists have had success by inserting a clear divider in the middle of the tank and allowing the male to get used to his potential partner this way, removing the divider after a few weeks. There are no guarantees even with this method, though, and others prefer to keep the sexes separated by a divider at all times, even going so far as to drill holes in the divider to facilitate the transfer of sperm without the need for the fish to ever share the same space.

By far the best way to get a pair is to buy a minimum of six young fish and grow them on together, allowing pairs to form naturally. Once the first pair is spotted (this is usually quite obvious, as the others will most likely be cowering in one corner of the tank), the other fish should be removed immediately for their own safety.

Once you have a pair they should breed without too much encouragement from you. When in spawning condition, the nuchal hump of both sexes will increase in size. Courtship can be quite a prolonged and sometimes violent affair, with much tail slapping and gaping by both sexes. The female also tends to rub her lateral area along the hump of the male. Have a tank divider to hand at all times as the male can turn on his supposed mate at any time. There will also be a lot of digging activity by both fish. Just prior to spawning itself the ovipositor of the female will be clearly visible. The eggs are usually laid either in a cave or on a vertical rock surface, although in the absence of these virtually any solid surface will do. Parental care is excellent and a joy to watch, with both sexes tending to the eggs and defending their territory against all comers. This can include the fingers of unwary aquarists, so take due care if performing tank maintenance during this period.

The eggs hatch in 2-3 days and the fry are then moved to a pre-excavated pit in the substrate. They become free swimming in another 5-7 days and at this point it may be wise to install the divider to protect the female from the now hyper-aggressive male. Similarly, don’t be tempted to remove the fry just yet, as this can cause the male to become a real psychopath. If the female has survived without additional protection and the young are removed, the male may attempt a second spawn, and if the female is not ready she may be killed by the confused male.

The fry can be fed on brine shrimp nauplii initially, before being offered supplementary dried foods. They grow very quickly under the correct conditions, and are a plain greyish colour initially, starting to change colour at around 2-2.5″ in size.

NotesTop ↑

Previously included as a member of the genus Cichlasoma, the midas cichlid is often confused with the red devil, A. labiatus. The two can be distinguished through differences in morphology. As suggested by its scientific name, A. labiatus often possesses characteristically large lips, although this is variable and should not be used as a defining indicator of species. More reliable differences include the bigger nuchal hump and more thick-set appearance in A. citrinellus.

Ther midas exists in many natural colour forms, most of which are dependant on type locality. There are a few man-made varieties also available. These include white, grey, yellow, orange, red, barred and piebald forms. Unsurprisingly, it is the more colourful variants that have become popular in the aquarium hobby. Unfortunately, intentional hybridisation between this and other species has occured extensively, giving rise to abhorrent “sport” fish such as the parrot cichlid and flowerhorn.

Despite its aggressive nature, it remains one of the most popular aquarium species among cichlidophiles due to its endearing personality. Captive specimens quickly learn to recognise their owner and exhibit a level of intelligence far beyond that of most commonly kept fish. Indeed many owners have been able to train their pets to perform various tricks in return for rewards of food.

Some wild populations of A. citrinellus have been shown to exhibit some interesting evolutionary biology. Ordinarily a new species develops when some population of an existing species becomes cut off from the rest of the flock by some kind of physical (usually geographic) barrier. This phenomenon is known as allopatric speciation. Much rarer (or at least, more difficult to prove scientifically) is a process called sympatric speciation. Here a new species arises when certain individuals in a population begin to breed only among themselves, ignoring others of the same species. A population of A. citrinellus inhabiting Lake Apoyo, a volcanic crater lake in Nicaragua is believed to have undergone this process, with a “new” species, A. zaliosus, arising to occupy a different ecological niche in the lake. Whilst populations of citrinellus exist in other, surrounding waters, zaliosus is endemic to Lake Apoyo. Given the similarity of the two in terms of DNA there is compelling evidence to suggest that sympatric speciation has occured here, feasibly within a period of 10,000 years (a mere blip in evolutionary terms).