Appearance: Named for the Greek root iodes, meaning either the color iodine or iron rust, Iodotropheus sprengerae is adorned with both colors. Their faces are painted a rust color while their bodies take on a deep lavender purple.
Sometimes they will have barring down their sides but this usually isn't apparent in mature adults. Rusties are sometimes confused with Labidochromis vellicans. They are easily distinguished by noting the more pointed head of L. vellicans.
Sexing: There is no color difference between the sexes; both males and females achieve a very dark purple color; however, females are less intensely marked. Males often have more egg spots and a longer anal fin as well. Males will also grow larger and faster than the females and will be more aggressive toward their own species. Rusties are considered a dwarf mbuna so size ranges from 3 to 3.5 inches. They can get larger than this, but not usually.
Behavior:I. sprengerae is non-territorial and a relatively non-aggressive mbuna. Since they are not very aggressive it is possible to keep several males in a tank 48 inches long. The only aggression displayed from this fish is inter-species aggression from male to male or male to female and this will rarely result in injury or worse. These should not be kept with large and more aggressive mbuna unless given tank space and hiding places.
Breeding:I. sprengerae is one of the easiest mbuna to breed due to their small maturity size (1.5inches). Their breeding will be rather constant when they reach maturity, breeding whenever possible. Their fry counts will range anywhere from 5-50.
My Opinion: This is a great fish for the beginner due to its peaceful behavior. It's also a good choice for those wanting to keep mbuna in smaller tanks. Rusties will readily spawn for the novice, giving him or her a nice introduction to the spawning behaviors of mouthbrooding cichlids. This is one of my favorite fish for many reasons, but perhaps most of all because they reach sexual maturity after a mere 14 weeks or at 1.5 inches. □