Click image to enlarge Keyhole cichlids by Oliver Lucanus.

Q. I have a 48-gallon aquarium and would like to keep keyhole cichlids in it. I’d also like some other noncichlids, as well. What’s the best way to set up this aquarium so both the keyhole cichlids and other fish do well? Any specific comments about aquascaping, the number of fish, filtration and required maintenance would be great.
Shelly Blackwell
Fremont, CA

A. The keyhole cichlid (Cleithracara maronii) is one of my favorite South American cichlids. It is extremely peaceful, behaviorally manageable even when spawning and is as easy on its tankmates as it is on the aquascaping. With perhaps its modest color pattern the only possible exception, it really is the perfect cichlid.

In its native habitat, the keyhole cichlid is a stream-dweller found in areas of reduced water flow and abundant cover in the form of fallen branches, leaves and sometimes flooded terrestrial vegetation. In the aquarium, it is a relatively easy habitat to simulate. Start with a layer of sand or fine gravel, and add a number of small twigs and several smaller pieces of driftwood. Plants are optional, but an aquarium with a mixture of wood pieces and plants tends to look more pleasing than one without them. Add the plants in groupings, being sure to leave a number of open areas for the cichlids to explore and forage. Lighting can be relatively modest, assuming the needs of any plants used in the aquarium are met.

Filtration need not be anything overly complicated or particularly powerful. Although keyhole cichlids can grow to 5 inches, food intake and subsequent waste generation are modest. I’d suggest an appropriately sized hang-on-the-back power filter or canister filter, depending on your preference and perhaps a simple air-driven box filter for added insurance (if the power filter stops working for some reason). Perhaps more important than the type of filter you decide to use (as long as it is sized correctly) is a schedule of regular water changes. I’d suggest that for a 48-gallon with the bioload I suggest below, you change about 50 percent of the water every seven to 10 days. The only other maintenance items I’d specifically suggest you keep an eye on are things like temperature (should be between 78 and 83 degrees Fahrenheit.) and pH (ideally between 6.0 and 7.0). As for the number of fish, you could start out with a group of six young keyhole cichlids. However, as they grow and pair off, I’d suggest reducing that number down to a maximum of four. Add to that a small group of more surface-oriented species like silver hatchetfish (Gasteropelecus sternicla) or perhaps a few mid-water species like the larger Hyphessobrycon species, such as bleeding heart tetras or lemon tetras, and you’d have an interesting aquarium and one perfectly suited to the keyhole cichlids. Best of luck with them!