Helping you keep your aquarium beautiful and healthy


Escape from the Aquarium: The Tale of Larry the Blue Lobster

by Robert W. Bly, founder,

An addition to the aquarium that is both unusual and beautiful is the specimen sold in fish stores as the "blue lobster." But it is not a lobster - it's a crayfish with a gorgeous cobalt blue color.

They are typically sold when they are young and about 2 inches or so. They can grow to 5 inches or even longer.

We have a habit of finding old aquariums (often our unused tanks discovered in the garage or attic), cleaning and setting them up once again, and then finding something to go with them.

In the case of Larry the Blue Lobster, we placed him in a 5-gallon plastic aquarium that had once held a beta fish - mainly because we didn't know what else to put in it.

The books say you need a minimum of 20 gallons for a blue lobster, but Larry seemed to thrive in the 5-gallon tank.

We fed him mostly sinking pellet food. Occasionally we gave him live food by putting in a few guppies, which he always caught and ate within 24 to 48 hours.

Because of his carnivorous habits, I would advise hobbyists against putting any crayfish in a tank with community fish. Before Larry, we'd caught a crayfish in a stream and kept him in a large bowl.

When we added a small frog to the bowl, the crayfish lived with him peacefully for a few weeks, until one morning we came in and found out they had fought to the death. In this case, the frog had won. But I am sure a larger crayfish would vanquish most smaller foes.

If you like the look of crayfish, a good substitute is a freshwater shrimp. The freshwater shrimp we have in our 92-gallon community tank is about 2 inches and similar in appearance to a crayfish, except he is grayish and not bright blue.

Our freshwater shrimp we have evolved his claws into fans that collect particles of food from the water. He is peaceful and, lacking pincers on his claws, can't catch or kill the fish.

Blue lobsters in particular and crayfish in general do get curious, climb about, and can escape their aquarium.

Once night, I heard clicking sounds on the stairs in our house. To my surprise, I found Larry, our blue lobster, walking to the edge of one step and falling to the next.

He had escaped his 5-gallon plastic tank through the tiny opening in the hood for the filter. I missed stepping on him by inches. We blocked the opening with duct tape, and that seemed to curb Larry's nocturnal strolls throughout the house.

One really neat thing about crayfish is that, as they grow, they form new shells and shed their old ones.

It helps to remember that. The first time Larry did this, I looked at the tank and saw an empty shell. Larry had hidden behind a decoration in the tank, so I thought he had somehow died during the night. Then I looked around some more and found Larry alive and well.

Larry's life came to a mysterious end. One morning, I checked the tank and he was gone again. Somehow, he had gotten past the duct tape barrier. This time, we could not find him. So unless he got out the front door and walked across a busy main road to the stream across the street, let's all have a moment of silence for Larry the Blue Lobster.