When first introduced into your aquarium, leave the lights off to prevent the fish from going into shock. The one advantage the pajama has is that it doesn't seem to hide as much as the other species. There are apparently two species of pajama, one having better defined colors than the other. Next on the list are the blennies. For hobbyists seeking bright colors, these fish won't do at all, but they have great personalities, are very hardy and only grow to about 4 inches.
Most blennies lack a swim bladder and therefore stay near the bottom of the tank.
Blennies have fairly large canine teeth, which they may use against other fish if they feel threatened, although this rarely causes any damage to the fish being attacked. The choice of species depends mostly on what is available. One species commonly seen in stores is the molly miller. There are some species of blenny that have forsaken staying near the bottom and spend most of their time swimming in open water. These are the forktails and the mimic blennies.