R.A.S. Fins & Friends

Iriatherina werneri, Thread Fin Rainbow Fishm

By Jacklyn McNaughton, Regina Aquarium Society

The Thread Fin Rainbow Fish come from New Guinea and Australia. They grow to a length of approximately two inches. They are a peaceful and lively schooling fish. They should be kept by themselves or in a suitable community tank containing only delicate fish.

The male has beautiful elongated fins. After an intense courtship by the male, spawning will occur in java moss, or in a wool mop. This is when one will see the full beauty of their finnage. Most rainbow fish spawn in the mornings, they spawn almost constantly but will have certain phases of increased egg production.

I set up a five gallon tank. The water was half hard and half soft rain, a sponge fry filter was added and the temperature was kept at about 76 degrees. Fresh java moss and a wool mop were added. A few days later a male and female were placed into the tank. Another five gallon tank was also set up to place the eggs in.

After a couple of weeks I began searching through the java moss for eggs. Any eggs that were found were picked out, placed on a small piece of java moss and dropped into the rearing tank. After another week or so I had around sixty eggs. Each day I looked for fry. One week - no fry - two weeks - no fry - day and night - no fry! I saw nothing! The tank was drained - little by little - looking - searching - for anything that moved - nothing!!

Then with determination - I tried again! I set up a three gallon rearing tank, upstairs on a stand by a window, but the window was shaded. Rain water was used and the temperature was 78 degrees. Again, I gathered eggs for one week or so. They again went into the rearing tank. A week later I saw about three fry swimming above the water line. They were so small - so minute - it was difficult to see them. A few days later, I was shocked - there were over 40 fry. I fed them sifted fry food and did a water change once a week, but the fry count dwindled after one month, I counted only around twenty fry. Another two weeks went by and I counted now only ten fry. I held my breath, as I needed five fry at sixty days. When the time came I still had seven fry left.

This species of fish has been a difficult challenge to hatch the eggs but most of all to keep the fry alive. I am trying again, as I have a few more ideas to experiment with. This is why spawning fish can be so exasperating but exciting, that's why we carry on and try again!