Keeping Fry Warm and Cozy in Winter
by Norm Ruebsamen
This time of year, our fishroom gets too chilly for some of the fry that need warmer water. My solution is the use of a heating pad under some of my fry containers. I purchased a regular heating pad, the kind used for sore muscles, at a discount store for about $14. I bought the larger size, 1 ft by 2 ft. and removed the fabric cover exposing the plastic pad so it would be waterproof. Its large enough to warm three shoeboxes as well as eggs in petri dishes and bags of eggs in peat. The pad has settings of low, medium and high. I keep it set on LOW which seems to hold a steady temperature of 80 degrees. So far it has worked very well with Rivulus Obscurus fry. The fry used to disappear one by one, now I have many more fry that make it to the young adult stage.
I am currently experimenting with the use of the heating pad and sex ratios. Some of the fish that I keep seem to be sensitive to temperature when it comes to sexing out. I have eggs and newly hatched fry of A. geryi Boke both on and off the heating pad and hope to see a much more even sex ratio in the fry kept at 80 degrees.