Clownfish

Most of the named clownfish in a shop are captive-bred colour lines of the ocellaris and percula: snowflake, picasso, black ice, the storms, DaVinci, platinum, mocha, Wyoming white and the rest. They are the same fish underneath and take the same care as a plain ocellaris, 3.1 inches (8 cm) and 20 gallons (75 liters). They are among the hardiest marine fish sold. The maroon lines (lightning, gold nugget, gold stripe and white stripe maroon) are the exception: they are maroon clownfish and carry the maroon's size and temper. The catalog lists each designer form under its parent species so the care facts stay in one place.

Every clownfish is a sequential hermaphrodite, and all of them change the same way. Each starts life as a male, and the largest fish in a group turns female for good. The next largest becomes the breeding male and the rest stay small. The ocellaris, percula, maroon, Clark's, tomato and skunk profiles all say so, and the designer forms are the same fish underneath. The way to get a pair is to buy two small juveniles of the same species at the same time and let them sort it out. Two adult females fight until one dies, two adults of unknown sex usually do, and different clownfish species fight in the same way. One species per tank, one pair per tank. The maroon clownfish is marked aggressive. A maroon female rules a 40 gallon and only tolerates a male much smaller than herself.

Captive-bred clownfish have never seen an anemone and do not miss one; they host in a coral, a powerhead or a corner of the tank instead. The anemone is the harder animal by far: it needs a mature tank, strong light, stable water and a keeper who has already succeeded with corals. The bubble tip anemone is the one to try if you want the pairing. It is marked medium, reaches 11.8 inches (30 cm) and lists 30 gallons (115 liters). The long tentacle anemone is the other medium host. The malu anemone is also marked medium and hosts only Clark's clownfish, and only occasionally. The magnificent and sebae anemones are marked difficult, and the large carpet anemones (Haddon's, gigantea and Mertens') are difficult and eat fish. Most species profiles list which anemones that clownfish hosts, and every anemone profile lists the tank it needs.