The tiny bouncer of the riverbed. It is one of the smallest of the bully family. It rarely grows bigger than a finger. But what it lacks in size, it makes up for in attitude. A fish with a napoleon complex. Males during breeding season turn a stunning electric blue on their cheeks, gills and fins. It looks like a little fish dipped in neon paint. A fish that wears its anger as colour. Bottom-huggers with a temper. Bluegill bullies sit on gravel. They are propped up on big paddle-shaped pectoral fins. They watch for intruders. If another fish gets too close, the male charges. Mouth open. He chases it away from his patch of rocks. Dedicated dads. The male finds a nice flat stone. He cleans it off. He convinces a female to stick her eggs to the ceiling of his little cave. He then guards the eggs with his life. He fans them with his fins to keep oxygen flowing. A father who does not sleep. A picky eater. Bluegill bullies only eat small soft-bodied insects. These include mayfly and stonefly nymphs. They cannot crush snails or chew on plant material. This means they need a stream full of clean gravel and healthy bug life to survive. A fish that demands clean water. To find a bluegill is to find a healthy stream. It is a small grumpy electric-blue guardian of the cleanest water in New Zealand. It is the indicator species for ecologists. The fish tells, without saying a word, whether the river is winning or losing against the farmers and the developers. The stream is clear. The gravel is clean. The bluegill sits on his stone. Electric blue and furious. He guards his eggs. The water flows past. The farmer pumps from the river downstream. The bluegill does not know. He just guards. In Māori tradition, the smaller bully species did not have distinct names. This is likely because they were too small and too hard to catch to be worth the effort. They were simply the little fish in the stream. Today the bluegill remains the indicator species for ecologists. It is the fish that tells you, without saying a word, whether the river is winning or losing against the farmers and the developers. Mana whenua observe these small indicators of stream health.