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R.A.S. Fins & Friends
Oryzias Latipes - Japanese Rice Fish - Medaka
by Jacklyn McNaughton of the Regina Aquarium Society

These fish can be found in east Asia - Japan, China, and South Korea. They are a peaceful fish, suitable for awell planted community aquarium, if the tank mates are not large.

As a rule the males are more slender and their anal fin is larger and ends more pointed. The coloration is more intense. They will grow to a size of about 2 1/4 (5.5cm).

They like medium to hard water (10-15 degrees dGH) Ph of 7.0 and a temperature of 64 -75 degrees F (18-24 degrees c) They like aeration and water movement. The water should be clean.

I knew very little about Rice Fish when I purchased a trio of two females and one male. They were placed into a small three gallon tank with the temperature and water requirements were as I had mentioned. I placed in the breeding tank a sponge fry filter and a wool mop. At the same time I also set up a tank for hatching the eggs.

I gave the fish a few days to become accustomed to their new home, then every 2-3 days I removed the wool mop and squeezed it out. Sure enough, I always found 4-8-10 eggs clear as glass. I picked them out, attachedthem to a small piece of java moss and placed it in the rearing tank. After a week or so I had over 80 eggs. The eggs will hatch in 10-12 days. I kept a record of how many eggs I transferred and the dates. After 10 days I found one small fry, them 3 and finally 5. I wondered why only 5 hatched out of 80 eggs.

Because I like to experiment, I set up another three gallon tank with RO water - ph 7.0 a fry filter and kept the temperature around 80 degrees. I again gathered eggs for another week and retrieved another 80. After 10days I began seeing fry and after a couple of days I counted over 30 fry. Now I was satisfied.

Now during this time, I mentioned I knew very little about these fish. I noticed one female had a string of eggs stuck to her bottom anal fin. I was shocked and wondered if this was normal or maybe she had a problem andcouldn't get the sticky eggs off. So on two occasions I caught her in a small net and gently removed the eggs. On placing her back into the tank, she appeared to be unconcerned with what I had done. The eggs I placedinto the rearing tank.

Then, luckily I received a new reference book. I learned that the female may continue to carry the eggs in a bundle in front of the anal fin. The eggs are linked together in a grape like cluster and will be brushed off onplants, etc. Now I knew it was perfectly normal for the eggs to be attached to the female. Problem solved - I was only trying to help.

The fry have survived and grown and have been easy to raise. With each water change I have added hard water and they are still content and growing. They have been fed dry sifted fry food and later live brine shrimp.

I was pleased to have the chance to breed these fish because we learn something new each time. Now with a little more knowledge and experience we can carry on and try something new again.