Aquarium tour: The Picasso Triggerfish

One of the most colourful marine fish we have on show is or Picasso Triggerfish, Rhinecanthus aculeatus. Triggerfish belong to the same order as the pufferfish, the Tetraodontiformes, but have a different means of self defence. Their skin is covered with very tough scales, and in the dorsdal and anal fins there are locking spines. When erected, these spines make the fish hard to swallow, and they are also used for wedging the fish into crevices in the reef rock, which is where they spend the night.

Aquarium tour: Arrowhead Pufferfish

Next to the brackish water display is a tank that most of the public walk past, as it appears at first glance to be empty. This is their loss, as it actually contains two of the oddest fish we have, the Arrowhead Puffer fish Tetraodon suvattii.

Aquarium Tour: Archer Fish

T.jaculatrix

The next tank along contains a selection of species from mangrove or estuarine habitats. The most distinctive of these are the Archer fish, Toxotes sp. There are at least seven different species of Toxotes, but the fish we have are probably T.jaculatrix or T.chatareus, which are the species most commonly seen in the aquarium trade.

Aquarium Tour: Here be Dragons

Gold form S.formosus

Next door to the paddlefish aquarium is another large tank containing large fish from Asia. One of the most important species in the tank is some young Asian Dragon Fish, Scleropages formosus. They are especially significant because they are the results of what we believe to be the first breeding of this species in a public aquarium anywhere. Previous captive breeding has been in outside ponds, mostly in Asia.

A Tour through the Aquarium: American Paddlefish

The first large tank in the Aquarium is dedicated to a variety of ‘primitive’ fishes, whose ancestors split from the ancestors of more modern fish such as perch and carp in the distant past. Still surviving today, the Chondrostean fish are characterised by a great reduction in bone and a skeleton that is mostly cartilage. They also often have a shark-like heterocercal tail, and were at one time thought to be close to the sharks. It is now plain that they are modified ray-finned fish, and the surviving forms are not necessarily even closely related to each other. We have two species at Bristol, the Sterlet (a small European species of sturgeon) and the subject of this article, the American Paddlefish Polyodon spathula.