Rusty cichlid

Where they come from

Rusty cichlids (Iodotropheus sprengerae) are Malawi mbuna from Lake Malawi, mostly around rocky shoreline zones. In the wild they spend their days picking at algae and the tiny critters living in it. That background explains about 90% of their personality and diet in the aquarium.

Setting up their tank

Give them rocks, stable water, and some elbow room and they are pretty forgiving for an mbuna. I have had the best luck treating them like a rock-dweller that wants to graze all day, not like a "pretty cichlid" you can toss into a mixed community.

• Tank size: 40 breeder works for a small group, but 55+ makes life easier (less bickering, better territories).
• Hard, alkaline water: aim around pH 7.8-8.4 with decent KH/GH. Most people get there with aragonite, crushed coral, or Malawi buffers.
• Rockwork: stack plenty of rocks into caves and sight breaks. Use egg crate/light diffuser under the rocks if you are stacking heavy.
• Substrate: sand is nice (they sift), but fine gravel works too. I like sand with some crushed coral mixed in.
• Filtration and flow: overfilter. Mbuna are messy and you will likely run a heavier stock list.
• Temp: mid to upper 70s F (around 24-26 C) is a comfortable range.

They color up best with a bit of structure and some line-of-sight breaks. A tank that is just a few caves and lots of open water tends to turn into one fish owning the whole place.

What to feed them

Think "greens with protein as a side," not the other way around. Rusties are not as touchy as some strict herbivores, but you can still get yourself into bloat trouble if you lean too hard on fatty, meaty foods.

• Staples: spirulina flakes/pellets, quality veggie-based cichlid pellets, algae wafers (broken up).
• Good add-ons: blanched zucchini or spinach, nori on a clip, occasional frozen cyclops or brine shrimp as a treat.
• What I avoid: lots of bloodworms, beefheart, or high-fat predator pellets. They will eat it, then you might regret it.

How they behave and who they get along with

Rusties are one of the more reasonable mbuna, but they are still mbuna. Males will claim a rock and posture, and they will absolutely chase fish that look or act like rivals.

In my tanks they do best in groups, with one male and several females. Too few fish and the dominant male focuses on one target. Too many males and you get nonstop flexing and shredded fins.

• Great tankmates: other relatively mild mbuna that are not similarly colored, plus some tough dithers like larger synodontis catfish.
• Use caution with: very peaceful species, slow fish, long-finned fish, and anything that wants soft/acidic water.
• Avoid mixing with: aggressive bruisers (some Melanochromis, big Metriaclima/"zebra" types) unless you have a big tank and know the vibe you are building.

Breeding tips

They are mouthbrooders, and once they settle in they breed pretty readily. If you keep a male with a few females and feed well, you will eventually notice a female holding - she will stop eating and keep a "full" look in the mouth.

• Ratio: 1 male to 3-5 females keeps pressure off any single girl.
• Spawning spot: a flat rock or little cave near the male's territory usually becomes "the" place.
• Holding time: roughly 3 weeks give or take, depending on temperature and the female.
• Fry plan: either strip the female (if you are comfortable) or move her to a quiet holding tank near the end. In a busy mbuna tank, many fry get eaten quickly.

Common problems to watch for

Most rusty cichlid problems come down to three things: diet that is too heavy, water that is not kept up with, and a social setup that lets one fish terrorize everyone.

• Malawi bloat: swollen belly, stringy white poop, hiding, refusing food. Often tied to stress plus rich foods. Tighten diet, improve water, and address bullying.
• Aggression and fin damage: usually from too many males, not enough rock cover, or a tank that is too small for the mix.
• Ich and other stress stuff: shows up after big swings (temp, pH, or a rough new fish introduction). Stable parameters beat chasing numbers.
• Hole-in-the-head/erosion: less common than in some cichlids, but poor water and a weak diet can bring it on over time.