A Stampeding Herd of Fish!

Location:Turneffe Islands Atoll - Belize

Day 4
by Wayne & Karen Brown

We are still diving at Turneffe Islands Atoll. Today we ran into a school of fish. Actually they almost ran into us! Remember the little damselfish we showed you yesterday? It has an algae garden that it guards and eats. The damselfish tries to chase away any fish that tries to eat its algae. It doesn't matter what size the other fish is, big or small. If we get too close to its algae garden it will even try to chase us away!

If you are an algae eating fish how can you get some of the damselfishes' algae? The way some fish do it is by traveling in a herd (actually a big school). The damselfish can chase one, two or three fish away, but how can you chase away a whole herd? The small lonely damselfish can't chase a big school of larger fish away.

The fish that almost ran into us were a school of blue tangs. They mob the damselfishes and eat their algae. This works so well that other fish will join the tangs as they mob the damselfish. We saw a parrotfish sneaking in with the tangs to eat some algae.

The algae eating fish are good for the coral reef because they eat the algae that is covering the delicate corals. Corals need sunlight to survive and grow. The algae blocks the sunlight but after the fish pull it off and eat it, the coral will have the sun shining on it again.

Best fishes,.
Wayne & Karen Brown


Turneffe Islands Atoll, Belize

Position: 17º 09' N / 87º 55' W
Air Temp: 87ºF
Weather: light breeze, sunny with scattered clouds and calm seas.
Water Temp: 81ºF

Karen swims along with a large school of blue tangs. Blue tangs eat algae-eating fish.

These blue tangs eating some of the algae garden of a damselfish. There are so many tangs that the damselfish can't chase them all away!

A parrotfish sneaks in with the tangs to eat some of the damselfishes' algae. (Can you find the parrotfish? It is green and has a some yellow on its tail.)

This is a dusky damselfish. It is only about 4-5 inches long, but it will chase away fish a lot bigger than it is. Notice that it is guarding the brown algae patch behind it.


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