Frequently Asked Questions Various questions either unanswered or uncategorized.

Updated April 2, 1998

NOTE: Discus keeping is not an exact science. Some may call it an art. This document contains answers from my own experience, from reference books, and in general terms from information gathered by running the Discus-L mailing list for several years. Any direct quotes, should they appear, are used by permission.

Information contained in this document is provided on an AS-IS basis. If you use it you do so entirely AT YOUR OWN RISK. Every effort will be made to provide accurate information, but I have not tried everything listed here myself. What works for one person may not work for another. As always, use your own common sense.

This document is very much in progress and is subject to change as new knowledge is gathered or new questions are added.

Breeding Questions

Q. What do designations such as F1, F2 mean when describing discus?

Q. I have a pair of discus with newly hatched discus fry that can't seem to find the parents to feed. What can I do?

A. If they're a new "couple", give them a few chances to "get it right". First-time discus parents often don't figure out what to do for the first few spawns. They may not know what to do to "attract" the fry. I've heard that this happens more with pigeon blood discus than with some other strains because they don't darken up as much for the fry to see them. One thing that sometimes works is to put a small light over just one area of the tank to attract both the fry and parents to the same area. Another thing you could try is artificially raising the fry yourself, but it is a lot of work and they require constant attention. Jack Wattley describes how this is done in one of his books.

Q. I have a pair of discus that spawn but always eat their eggs. What can I do?

A. If they're a new "couple", give them a few chances to "get it right". First-time discus parents often don't figure out what to do for the first few spawns. If this doesn't work, then you might try putting a fine wire or plastic mesh around the spawning area, which will allow the parents to fan the eggs, but not get to them to eat them. Choose material that will be safe in an aquarium and is not sharp so the parents will not injure themselves if they try to get through it or around it.

Q. I have a pair of discus that spawn but always eat their fry. What can I do?

A. If they're a new "couple", give them a few chances to "get it right". First-time discus parents often don't figure out what to do for the first few spawns. If this doesn't work, you might try removing one parent and seeing if the other one will take care of the fry. If both parents are eating the fry your only real choice is to raise thr fry artificially, but this is a lot of work and they require constant attention. Jack Wattley describes how this is done in one of his books.

Q. What is the best way to hatch brine shrimp?

Water Quality questions

Q. How often should I change the water in my Discus tank?

A. Simple answer: as often as possible. There are a couple of things to watch out for, however. If you change a lot of water and suddenly one or more fish start acting strangely, then you may have a water poisoning problem and changing more water will make it worse. What to do in a case like this is filter with activated carbon (even if you don't normally use it). With luck, the carbon may take out whatever toxins are in the water.

If you can store your water in a holding container and make sure it's conditioned and checked for quality before the water changes, that will lessen the chances of a toxicity problem, but not everyone can do this.

There are as many different answers to the "how often" question as there are discus keepers. My personal recommendation is 25% a week MINIMUM. Many people change much more often. It also depends on how large the tank is and how many fish are in it. A large tank with a few fish will need less water changes than a small tank with too many fish.

Q. What is the relationship between nitrite and nitrate. Do you need test kits for both? Nitrate is the final product of the nitrogen cycle, which goes from Ammonia->Nitrite->Nitrate. You should at least have a Nitrite test kit as Nitrite poisoning can be as deadly as ammonia poisoning. Of course, having an ammonia test kit is mandatory. A Nitrate test kit is also a good thing to have, because when your Nitrates get past an acceptable level, you need to perform a partial water change. However, there are other ways to tell when water changes are needed, so I consider a Nitrate test kit helpful but not mandatory.

Probably the single biggest factor in discus keeping is water quality, so the more you can do to ensure your water is of the quality they require, the better.

Q. What is the difference between buffering capacity and pH?

A. pH is defined as the Power of Hydrogen atoms in the water. It is read on a scale from 0 (totally acid) to 14 (totally alkaline). Discus like somewhat acid water. I like to keep mine at around 6.5. I have heard some breeders recommend going as low as 5.5.

Buffering capacity is the ability of water to resist changes in pH. Water with very low buffering capacity can experience rapid large pH changes, so this is something you'd naturally want to avoid.

Q. Does baking soda (sodium bicarbonate) raise the pH or the buffering capacity or both?

A. Both. It raises the buffering capacity and, as a side effect, also raises the pH.

Q. What's the difference between baking soda (sodium bicarbonate, NaHCO3) and sodium hydrogen carbonate?

A. They both act similarly as buffers. From my experience sodium bicarbonate raises pH as well. I don't know about sodium hydrogen carbonate.

Q. Will adding acid buffer lower pH as well as providing buffering?

A. Seachem's Acid Buffer claims to both lower the pH and buffer the water against further changes.

Q. What about buffers that contain phospates? Why do some companies tout "phosphate-free" buffers?

A. A large amount of phosphate in the water can increase algae growth. Therefore, it may be desirable to cut down on the amount of phospate you add to your water.

Q. Is it safe to lower pH with vinegar?

A. It shouldn't hurt the fish, but the generally accepted answer is not to use it because it may cause a large algal bloom.

Q. Is is safe to lower pH with citric acid?

Q. What is the most reliable method of measuring pH?

Q. Can anything cause "false" pH readings?

Q. What ammonia test kits will read correctly when using AmQuel?A. Kits based on Nessler reagents will not. Kits based on Salicylate reagents will. Kordon makes one.

Q. Is it possible to have a high level of nitrites without having an ammonia spike first? Is this harmful?

A. Yes, this is possible and the nitrite can be more deadly to the Discus than the ammonia. More details will follow.


Q. I medicated my discus with Fluke Tabs or other medicines. Now they are very shy and run from me instead of coming up to eat. Why?

A. This is a common reaction after using Fluke Tabs and other medications. The best thing to do is give them time, and they will usually be their "old selves" again in a couple of weeks or so.

Q. My fish has tapeworms. How do I get rid of them?

A. First choice is Droncit, a brand name for Praziquantel. You'll probably have to get it from a veterinarian. It is not sold over the counter in the USA, though one member reports that a product called Drontal (a dog wormer), containing praziquantel, is available elsewhere. How to dose the fish is an issue here. I will try and get some dosages up here from books or from people who've used it.

Second choice is Flubenol, which does not require a prescription, but your local fish store isn't likely to have it either. I will try to get a source for Flubenol and suggested dosage up here.

Third choice that some claim to work is Fluke-Tabs by Aquarium Products. Fluke-Tabs does claim on the package to get rid of tapeworms. Be careful with Fluke Tabs. Do not use it at a stronger dosage than what is listed on the package. It's strong stuff and some have reported bad side effects such as headstanding. Other side effects may be that the red color in the eyes will fade, but this usually comes back in time. Headstanders caused by Fluke Tabs usually also stop headstanding in time.

Q. What is Flubenol and how do you get it?

A. Flubenol is a trade name for a product containing a certain percentage of flubenzadole. You can get it from a veterinarian, or there is at least one mail order place that carries it. When I find the info I'll add it to this page.

Q. What medications contain Formaldehyde and Malachite Green?

A. "Contra Spot" by Tetra and "QuICK Cure" by Aquarium Products are two. I'm sure there are others. Make sure you aerate your tank well when using any product containing Formaldehyde, as it tends to deprive the water of oxygen.

Discus Nutrition

Q. My discus won't eat. What do I do?

A. First, don't panic. Discus can go awhile without eating. I wouldn't recommend it but a healthy fish can go a few days without eating and not die. You may have to "coax" them to eat with some live food or blood- worms. Of course there are parasite risks with live food and bloodworms but better to have to treat for a case of parasites then end up with a starved fish. You should also think that if the fish is not eating, something may be wrong with it. It could have an intestinal parasite or other disorder already, and just not want to eat. Watch for signs of intestinal diseases, like stringy white feces. Also check your water parameters and do a partial water change. There could be something wrong with the water that is causing the fish not to eat.

Q. Can discus be kept healthy with just flake food?

A. Discus require a balanced diet, just like humans do. They may not eat the same things but they do require balance and variety in their diet. If your discus will eat flakes (and not all will) make sure you use vitamin enriched flakes such as Tetra's 5-Star. There are other products too, but make sure you get one with more than just vitamin C added.

That being said, I have seen perfectly healthy discus raised from juveniles on nothing but Tetra Bits. I'm not going to say that will work for everyone, but I've seen it done.

Q. What are the best automatic feeders to use if I'm going to be away?


Q. How long does a typical discus live?

A. I have heard of discus living up to 10 years. I would guess that the typical age is somewhat less than that. As of this writing, my oldest are almost 4 years old. I got them March 23, 1994.

Q. How do I tell a quality discus at a store?

A. A quality discus should be almost round. There should be no signs of disease, no frayed fins, etc... (All the things you'd look for in any other fish). When you approach the tank they should come to the front of the tank. The eye should be proportional to the body size. A small fish with large eyes may be cute, but may also be stunted.

Also watch out for a very small fish (1-2") with bright coloration. This could mean the colors have been artificially enhanced with hormones.

Q. What is the average size of the adult discus?

A. This is another question with no absolute answer. The adult discus can range from around 5" to around 8" from the nose to the base of the tail.

Q. How can you tell the sex of a discus?

A. There is no absolutely reliable way to do this. Some methods have been proposed, such as the male having pointed ends on the dorsal fin, but I've seen exceptions to this. In discus pairs I've seen, the male is usually larger than the female, but there are probably exceptions to that also. In general the female's ovipositor is a little shorter and more blunt than that of the male. The only real way to identify sex is to wait for them to spawn. At this point it's easy to tell the females. :) If a pair forms, the female will lay the eggs and the male will go along behind her and fertilize them. Only if the eggs hatch can you really be sure who's who. It is possible to have two females pair off. I have a "pair" of females. They do everything together, even matching each other's motions when they're telling me it's feeding time.

Q. When does the average discus reach maturity?

A. This will vary, but in about one year. Some will reach it sooner, some later.

Q. What's the most reliable heater to use? What if one breaks?

Q. What if the power goes out?

A. Blankets wrapped around the tank will help hold in the heat. Air via battery powered air pumps is important. I've debated using an oil lamp in the cabinet under the tank for heat but I don't know of the safety of doing this. You would not want the bottom of the tank to get too hot (or start a fire!) so if you try this it should be monitored at all times. I've heard of putting hot water into a closed container and placing that in the tank for heat also. Don't pour hot water directly into the tank. Mix it with some tank water in a bucket and check to make sure the temperature is not too high before adding it. If you can pour it in from above the tank a little ways you can add some aeration as it goes in.

Battery powered air pumps are something that everyone should have around, along with a spare supply of batteries. Hagen makes one that I've occasionally seen in That Fish Place's catalog. You can also sometimes find them at "bait and tackle" shops where they're sold as minnow aerators. I have considered buying one or two of those "uninterruptable power supplies" that are used for computers. These could be used to keep the tank filters running, for a while anyway. I probably would not try to run the heaters from one of these as they'd take too much current and deplete the UPS batteries too soon. Since the UPS's are made to run a computer that takes a couple of amps or more, running a few low-power fish tank filters should make them last much longer. I have not tried this but it seems to make sense. I have also considered a power inverter running from a car battery, which would keep things running as long as the car was run to occasionally recharge the battery. Again I havn't tried this but in a long outage I'd be trying everything I could think of.

Q. What is peat used for?

A. To soften the water and lower pH. Some like the slight coloration it adds to the water.

Q. Where can I buy peat in bulk sizes so it's less expensive?

A. One member reports finding it at a store such as Home Depot. The main thing to watch out for is that there are no chemicals added to the peat. If the bag happens to say it's safe for aquarium use, that is even better. Be careful when buying peat this way.

Q. Where can I find the book "Brand New Discus"?

A. I have sometimes heard this can be found at Borders Bookstores, though I can't personally verify this. I believe it is out of print.

Q. Where can I find the book "Discus Health?"

A. This book is out of print as far as I know. If you see a copy and you want it, buy it! Don't wait for bargain prices. There are still copies that pop up every now and then.

Q. What kind of companions can I have in a Discus tank?

A. The book Discus In the Community Tank is a good reference for this.

Q. Can I keep Angelfish with Discus?

A. There are some who claim to do this successfully, but more often than not I would say no. I don't do it myself, though I do keep both species separately. Reasons for not doing it is that Angelfish are voracious eaters and may keep the Discus from getting enough food, and Angelfish can be carriers of diseases that they seem to cope with much better than the Discus can.

Q. Who are some suppliers of aquarium plants?

Q. What are resistivity and conductivity and how do they relate to Discus keeping?

Q. I have a snail problem in my Discus tank. How do I get rid of the snails?

A. One way to get rid of snails is to add fish to the tank that like to eat snails. A good example is the Clown Loach. Beware though that Clown Loaches can get BIG.

Q. Many people use salt to help cure minor fungal infections or other things. Is it ok to keep salt in a Discus tank all the time?

Q. How should new discus be quarantined? Should preventive medications be applied and if so, which ones?

Copyright © 1998 David M. Hardy. Publication here does not indicate the material is in the public domain.
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