Tag: breeding

Sexing koi

Posted on by TheFishVet - Richmond's School of Fish

To follow on from my previous post, text books will often tell you that a male koi will be slimmer and have a longer head. Female kois will have a wider, deeper body and a shorter, more feminine head.

Those in the know will also add that during the breeding season, the male fish will be rougher to touch along their flanks and over their operculae (gill covers). The females on the other hand, will have smoother skins.

Your female kois will be roeing up now in preparation for spawning which would occur over the next few months. You might notice males showing more interest in the females and will chase them when they are ready to spawn.

Sexing fish

Posted on by TheFishVet - Richmond's School of Fish

Sexing fishes are one of the most common things people ask fish keepers. Many would want to purchase a male and a female fish.

So, how do you tell the difference between a male and a female fish? In general, male fishes tend to have longer or more elaborate finnage and more intense colouration. Females tend to be bigger and more rotund in order to carry their eggs. Some species such as the live-bearing guppies, mollies, platies and half-beaks have their anal fins modified from the fan shapes (seen in females) to elongate tubes known as a gonopodium. Sharks and rays have similar long appendages known as claspers.