Breeding Discus Part 4 – Infertility
Posted on
We have gone over the problem of Discus eating their eggs while spawning or shortly thereafter in a previous posting. Now we will go over fertility. We will go over what happens once the eggs hatch, but before the fry are free swimming next.
Fertility is an issue with Discus Fish and will significantly vary between different pairs. Some pairs will be totally infertile; other pairs will be infertile at first and then will become less fertile over time. On pairs that are fertile, the percentage of fertile eggs will range from 10%, in this scenario, about 80% fertility.
There are three typical causes of infertility for Discus. The first one is caused by the male not doing his job and not fertilizing the eggs. The second and third are biological and are due to either the eggs or sperm being genetically or chemically infertile.
When Discus lay eggs, the male should follow the female on a fertilizing run after she does an egg laying run. Some males only make the run after every few egg laying runs. It is my experience that these males tend to have a lower fertility rate. Some males will not fertilize at all. These tend to be the males that also are most aggressive on eating the eggs. There is very little you can do to change these males.
Some Discus Fish are infertile because of water chemistry. To optimize fertility, water temps should be kept constant between 84 and 88 degrees. Ph should be kept constant at 6.5. TDS should be low at 18 or less. Heavy filtration, if possible, is a big plus. I try and avoid doing water changes when they have spawned.
Discus that are genetically infertile will never be fertile. Keeping water temperatures above 96 degrees for over a week will usually result in the permanent infertility of Discus. Some Discus Fish breeders have been known to purposefully sterilize the discus they sell to keep others from being able to breed the strains they have developed. We would never do this.
