The Signifer Rainbowfish, or Pacific Blue-Eye Rainbowfish can grow to be almost 2 or 3 inches long, however, they are usually smaller than this in captivity. This is an extremely adaptable fish, meaning that it can be more flexible than others about its habitat and changing to a new tank. Most of them however will require a temperature at or below 82 degrees. This species of Rainbowfish is known for appreciating just a little bit of salt in their water. A 5 gallon tank is large enough for a group of Signifer Rainbowfish as these are a popular species to use in nano tanks. Stock about 1 per gallon, and keep with only non-aggressive dwarf species.