Using aragocrete rocks is one of the best things you can do for your tank. They will not deplete the ocean, or cause any environmental damage, and they are reef safe. Avoid the Thumb-splitters! Use aragocrete rock.

THESE ARAGOCRETE SCULPTURES ARE VERY LIGHT WEIGHT SO YOU GET LARGE ONES FOR LESS MONEY THAN WILD ROCK THAT SHOULD BE LEFT ON THE REEF.

Like all cities, these rocks have wonderful citizens; colorful sponges, interesting corals and invertebrates. However, like cities, wild rocks have their share of lowlifes, harmful creatures that are difficult to remove. Wild rocks contain pest algae that resumes growth as soon as the conditions are right.

One of these wild rock criminals is the notorious mantis shrimp. We have no mantis shrimp at GARF, because we use man-made aragocrete rock. Since we don't see these mantis shrimp, we were all very excited when a local hobbyist brought us a mantis shrimp that he had found in his tank.

Our reactions to the shrimp were very characteristic. Leonel, being practical, wanted to kill it right away. Leroy wanted to create a whole new aquarium for it, and I wanted to study it.

Mantis shrimps can grow up to 30 cm in length but start out as tiny creatures that burrow into holes in rock. Small mantis shrimps embed themselves in rock, and that is how they get into reef tanks: some unsuspecting hobbyist buys live rock and ends up with a monster.

You may be thinking "what's so bad about mantis shrimp?" Well, look at these claws:

Of course, thumbs are not the only thing that mantis shrimp will slice with their vicious claws. Mantis shrimp are highly predatory, and can decimate populations of fish and invertebrates. They lay in wait, like our praying mantises on land, and simply lash out at whatever prey is near. What a way for a beloved pet fish to go- cut in half by the claws of a mantis shrimp.

I have had several frantic calls from people, whose reef animals are being devoured by mantis shrimps. It is not an easy matter to remove mantis shrimp from an aquarium.

Their burrows are deep in the rock or sand bed, and when they come out, they move quickly. An aquarist with mantis shrimp can try to remove them with tongs, spear them or trap them in some kind of container.

However, if a capture technique fails, chances are it will never work. Mantis shrimp are capable of learning, and they will be cautious the second time.

As Leroy says, "You look at those eyes and you know they are intelligent."

Often, the only way to remove a mantis shrimp is to remove every piece of rock until the mantis shrimp's home is exposed.

I'm very glad we don't have any of these creatures living in the tanks at GARF. I'm also glad that I was able to observe this fascinating, but menacing animal in a safe way.

This is a special observation tank that Leroy set up specifically for the mantis shrimp.

It's a simple ten gallon aquarium, placed in our brood stock Palythoa tanks. Water pours down into it from a tray above and is siphoned out, using some old pipe and a soda bottle. This is how scientists set up field aquariums. Leroy learned how to create these during many field trips including two six week trips to Palau in 1979 and 1980 to study rare Chambered Nautilus with the help of the National Geographic society.

Eddie has made a lot of very nice aragocrete rocks. These rocks are made of a porous, stable material and have plenty of texture and space for corals to grow and fish to hide. I guarantee, 100%, that our aragocrete rocks are free of mantis shrimp.

EDDIE POSTMA'S NEWEST ARAGOCRETE^TM SCULPTURES

THESE ARAGOCRETE SCULPTURES ARE VERY LIGHT WEIGHT SO YOU GET LARGE ONES FOR LESS MONEY THAN

WILD ROCK THAT SHOULD BE LEFT ON THE REEF.