Research

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The following section is devoted to research topics. There are many subjects that are still unknown in the discus world. By collaborating together, much can be accomplished. The following is a preliminary list of suggested subjects that I hope will be added to by many of you. If something interests you please feel free to look into it and report back on the results. If you feel a topic is missing, feel free to forward your idea. Perhaps another reader will be interested in looking into it! Send suggestions to discuspage@juno.com

Tubifex culture -

Many discus keepers have found tubifex worms to be a very good growth stimulator. However, many discus keepers have also found tubifex worms to be an intermediate carrier of parasites. As far as I know, the specific parasites that can be passed by tubifex have not been specifically identified. The most common rumor is tape worm eggs and Capillaria. Knowing the specific possible parasites would be interesting. However, I believe that knowing how to culture tubifex on a small scale is an even more important endeavor. If tubifex can be cultured by the hobbyist, then known clean worms can be maintained and the growth benefits safely used for the fish.

Carbon in the discus aquarium - This is a VERY controversial and volatile subject. So much so that it has been banned off both of the discus mailing lists. The crux of the issue is that some discus keepers have found a correlation between carbon and hole-in-the-head (HITH) disease. Others have used it for years without mishap. Since there are several experiences in both camps, discussion usually degenerates to name calling and yelling about the absurdity of the whole issue. However, the interesting thing is that enough people have found a correlation to at least consider that there is in fact some sort of link. What were the other factors that came into play? Does carbon remove a specific vitamin or compound that prevents HITH? Perhaps the people who have used carbon for years without any problems had something in their tanks or fed something that replaced the vital compound. On the other hand, perhaps the correlation to carbon was mere coincidence. At any rate, research needs to be done in this area with controlled experiments.

Vitamin-D - Some time ago a reference was made in Diskus Brief (at least I think this was where I read it) that the addition of vitamin-D to the discus diet cured hole-in-the-head disease (unfortunately, I cannot remember which issue this was in. If anyone knows, please send in the reference). Since HITH is a common occurance in discus, finding a cure is an important goal.

Water Changes - Many people have found through experimentation that the more water changes, the better. Do you want your discus to achieve the fastest growth possible? Do massive daily water changes! The kicker is that water changes are labor intensive and generally viewed as pure drudgery (except for the lucky people who have installed automatic continuous water changing systems)! Is there anything that can be done to reduce the frequency and quantity of water changes while maintaining good growth rates? For that matter, is there anything that can be done to completely eliminate the necessity of water changes?

Growth Suppressing Hormones - Jack Wattley believes that all discus secrete a growth suppressing hormone that builds up and slows the growth rate of other discus. This hypothesis was extrapolated from a study done on tadpoles where it was found that the largest tadpole in a clutch maintains its size advantage by secreting a hormone that slows the growth of its siblings. Similar behavior seems to be in schools of discus. There are always a few discus that have a tremendous size advantage. Keeping the smallest discus with their siblings results in continued slow growth. However, moving these disadvantaged fish into their own tank generally causes a large growth spurt. Does a growth supressing hormone really exist or is this phenomenon caused by something more common like nitrates?

Supplemental Air - Some time ago, I had a divided tank with six juvenile discus on one side and six smaller juveniles on the other. A heater and sponge filter was on the side with the larger discus, and an airstone was on the side with the smaller discus. Both sides were fed equal amounts of food. Within a six month period, the discus on the side with the airstone grew to more than double the size the discus on the other side. This is very likely just pure coincidence. However, this may be a very important discovery. A controlled experiment should be done to prove or disprove the results.

Nitrates - What role do they play in the discus aquarium? Some aquarists feel they are harmless... other aquarists think they are a growth suppressant. Nobody seems to know for sure. Recently nitrate removal resins have come on the market. What effect does the use of these resins have on the discus aquarium?

Fry Mortality- It has been noted by several well known breeders (including Jack Wattley and Bing Seto) that fry mortality decreases if a light in the room is left on during the night. What is the mechanism involved here?

Garlic- A recent article in Diskus Brief noted that garlic in the discus diet has a substantial effect on Capillaria. This is an interesting topic that should be explored further. Are there any side effects? Does the effect diminish with time? What is the mechanism? (ie does garlic deter or kill the capillaria?) Are there other herbs that could be of benefit... perhaps Echinacea?

Spawn Triggering Conditions- Are there identifyable mechanisms that trigger spawning? The most common one that seems to be used is a water change with slightly colder water. Are there other conditions that influence spawning behavior? Can Discus sense atmospheric conditions? What about seasonal variations or EM fields?