A shoal of archer fish at the Blue Reef Aquarium in Bristol is being given target practice using artificial flies.
In the wild, these fish will shoot jets of water up to three metres in the air to knock prey into their mouth. However, staff at the aquarium feared that the fish had become too used to being fed with their staple diet of pellets and bloodworm and were losing some of their natural hunting skills.
To reignite their natural behaviour, the staff first decided to place food on the side of the tank. Blue Reef’s assistant curator Becs Smith is quoted saying: “Our first attempt was to stick pieces of food to the side of the glass and that seemed to catch their attention. They would position themselves directly below and take it in turns to spit until it fell into the water.”
“It was then we decided to take the experiment one stage further by devising the fake fly mobile and now it’s in place they’re really going for it.”
At feeding time the plastic flies are smeared with bloodworm and suspended on a mobile. Bits of food become dislodged whenever the fish score a direct hit and fall into the water where they are pounced on by the waiting shoal.
“Hopefully it will encourage them to behave as they would in the wild without us having to provide them with an endless supply of live flies,” Smith added.
Staff are keen to point out that in the summer when there is an abundance of live flies they hope the training will enable the fish to hunt their more natural prey too.
Found throughout northern Australia and south-east Asia, archer fish use their tongues and a groove in the roof of their mouths similar to a rifle barrel to produce the high powered water jets.
If the first jet misses, the fish fires a rapid follow up jet to bring the target down. If all else fails the fish can leap more than a foot out of the water to dislodge their prey.