Swimming posture

The Arowana should be gliding up and down the tank effortlessly and when it turns it should be very smooth and graceful. Its body should be exactly level horizontally when swimming, if it is not and it is at a slight angle it could mean a swim bladder problem. The fish are nearly always in the top 16 inches of the tank; make sure it stays there. Watch the fish as it moves. Its head should be very still with just the back half of the fish moving at all. If the fish is displaying a jerky or stiffness when swimming, this could be a sign of a sick Arowana.

 Tail Fins, Pectoral Fins

Watch the Arowana as it swims, are the fins at the tail spread open and are the fins at the front widespread? Fish that have their pectoral fins too close together at the front should not be bought. The color off all the fins must dark when you look directly at them with even fin rays. One thing to also consider is that some species of Arowana (like the Cross Back) have much smaller fins so don’t be put off by that.

Barbels

The Arowana whiskers (or barbels) need to be straight and both should be the same length. Closely inspect around the base of the whiskers to make sure there is no damage, this is where damage occurs the most. Color of the whiskers should be the same as the rest of the main body. A fish in good condition will have long/strong whiskers.

Eyes

Check very closely that the eyes are clear and not cloudy at all. They should be of a size that is in keeping with the rest of the fish’s body and they must not stick out too far from the head.

Body shape

The Shape should be broad and deep with a pointed head. You should really select a fish with a slight incline between its head and back. One of the big factors of price is the broadness and look of power of the Arowana. This can sometimes be nearly as important as the age or color.

Scales

Always look for an Arowana fish that has large scales that are very defined. They should be straight, aligned along the body with no crooked scales.

Gill cover

It needs to be flat to the body of the fish and be circular in shape. Watch closely as the gills move to make sure that the fish is breathing correctly. They should be small movements that you can hardly see.