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Illustrated Guide to Diseases and FAQ
 Forum Index > Diseases and Disasters  This topic is locked: you cannot edit posts or make replies.   Post new topic
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Joined: 08 Feb 2003
Location: Maryland near DC

PostPosted: 2003.02.18(Tue)19:03    Post subject: Illustrated Guide to Diseases and FAQ Reply with quote

True diagnosis online just from a loose description ("my fish is just sitting at the bottom, what's going on, what's making it sick") is close to impossible. All we can attempt to do online is make a good *educated guess*, so to help us help YOU as much as possible (and save us both some time), we ask that you please include as much information as possible about your setup.

When posting, we ask that you please AT LEAST include the following:



Tank size

Inhabitants of tank

How long tank has been set up for since you got it (including cycling methods)

Recent changes & fluctuations

If a disease problem, what are the signs and symptoms you are noticing (as specifically as possible; if you see a lesion for example, describe size, color, how frayed the edge is, if it is ulcerated or raised, how long have you noticed it, does it change in size, etc.).
If you have photos, even better! If you have problems posting those to the board, feel free to contact me personally, and we can work out an email exchange, I collect them for a disease photo archive I work with.

Any of the above is considered pretty important to know, and mentioning it in your first post will really help you get the fastest and most accurate advice possible, because you will invariably be asked it sometime further down by someone else before you get a reply. If you do not have a kit that tests for ammonia and nitrite, I strongly suggest that you purchase one; in the short term, you can go to the LFS (local fish store) and most will test these for you for free.

More info is always better than less, and you are not limited to the above; feel free to elaborate on other factors, such as pH, KH/GH, temperature, filtration, feeding/water change schedule, lighting, if you have live plants, if you feed live foods, if you have had any recent tank additions, tank dimensions, if you use quarantine/hospital separation methods, if you have had past outbreaks of disease in the same tank, if you have had bullying behavior or past ammonia spikes, if you have used medications (if so, what type and how long), any other suspicious circumstances you feel may help narrow the field.

Please note that the intention of this board is not to hold your hand step-by-step through every disease & disaster issue if you aren't proactive and show that you have a willingness to do reading outside of your own post. Most of us here will go to great lengths to help you, but we are a much more useful resource when board comments are taken *in conjunction* with outside research; by this, I mean try to read the FAQ (below), read linked disease articles, and read through past forum posts to make sure you aren't posting a problem that was just recently covered.

What follows below is a list of Frequently Asked Questions having to do with common aquarium problems. Tip on using this FAQ: Rather than scrolling through the entire list of Q&A if you have a specific question, you can go up to the toolbar on Internet Explorer, go to "Edit", and click on "Find". You can then type in a keyword to see if it is mentioned somewhere in this article.


Q: Why did my new tank suddenly turn cloudy, almost overnight?

A: It's most likely what's called a bacterial bloom. This usually happens when the nutrient content of your water is quite high, and the bacteria suddenly have a population explosion as a result. Don't panick, because this in itself is not necessarily something that will hurt your fish, but it is an indication of what your water values might be. This often occurs in relatively new tanks, which are not balanced places for fish to live (see cycling links below). Check your ammonia and nitrite levels, and if you don't have a kit yet, I strongly suggest you buy one. Suddenly cloudy water can also sometimes be caused by overstocking, overfeeding, or a relatively sudden change in the water conditions of the tank. Usually, just keeping up with regular water changes will allow the bloom to burn itself out in a few days, but perpetual cloudiness can happen in tanks which are always overstocked. Doing very large water changes (>50%) can actually be counter-productive, in that they will feed the bloom and continue the vicious cycle by introduction of more nutrients. If the cloudiness has a green tint to it, it's very similiar, only the bloom is caused by algae. In addition to nitrogenous compounds of fish waste feeding it, organic phosphates will also contribute.

Q: I see white, wiggling worms that are tiny and look almost like "cat hairs". What are they and will they hurt my fish?

A common free-living nematode at high magnification.

A: If they are not attached to your fish, chances are that they are harmless free-living nematodes. Parasitic worms tend to live most of their adult life cycle in or on the fish, not swimming out in the water, and nonparasitic nematodes are common in tanks where the nutrient content is high. Read this.

Q: My fish have started gasping at the surface and/or a whole bunch of them died after I just set my tank up--what happened?

A: Please check this article on the nitrogen cycle by Shawna, her other article on fishless cycling, or read up on new tank syndrome. Gasping is a sign of a gill problem, which for beginners is most often caused by ammonia poisoning in an uncycled aquarium that does not have "good" bacteria in the filter yet (it is also seen sometimes when people do too thorough a job of cleaning and washing out the filter, because they kill the bacteria that are there). Ammonia comes from fish waste, and is toxic to animals; it is degraded by bacteria, but it takes time to build up these populations. Please read the articles for more information. Red gills and gasping at the surface CAN also be caused by other agents, including gill flukes and other infections, but these are more uncommon.

Q: Why are my fish scratching against objects? My fish has white grain-like spots on its body, is this ich?

A well-progressed case of Ichthyophthirius (Courtesy of TFH magazine).

A: Scratching (also called "shimmying") is caused by skin irritation. One of the more common causes of skin irritation is a disease called ich. When it is well-progressed, you will see the characteristic 'salt grain' white spots on the skin, but in the earlier stages, you may not see this. If you suspect ich, read this. Irritation can also be caused by a number of other things, including other skin parasites (velvet, fish lice, anchor worm, etc), or even an irritant toxin in the water, but these are not as common (for more on various diseases, including photos, check here). A special note on this issue--skin diseases, especially ich (and the secondary bacterial infections that it predisposes the weakened fish to), LOVE to attack stressed fish (stress = a poor immune response). In addition to curing the direct source of the disease with medication, try and look for indirect causes of stress, including sudden temperature changes, sudden pH changes, recent addition of unquarantined fish to an uncycled tank, a recent ammonia spike, aggressive attacks by a "bully" fish, etc. Here is a very basic article on fish compatibility, and here is yet another article which covers some common fish diseases.

Q: My fish has a fuzzy white growth on it, is this a fungus?

A: This really depends. There are fungal diseases which infect fish, but there is also a very common bacterial disease called Columnaris which mimicks fungus. True fungal diseases (caused by species such as Saprolena) tend to be "furrier" and appear like bread mold, often growing on parts of the body which have already been infected and loving water which has gotten stagnant from lack of circulation. Columnaris is even more aggressive (faster moving, more life-threatening) in its growth and will attack healthy tissue; it appears as slightly "fuzzy" white patches that grow over all parts of the body. To differentiate the two, look at photos) of both, and compare "Bacterial skin infections" with "Body fungus".

Q: Why are my fish's eyes popping out and/or looking clouded over?

Pop-eye and cloudy eye seen together in a betta (Courtesy of Jazzo of AofA).

A: Pop-eye and cloudy eye can have numerous causes, and almost all are related to stress and shock of sudden water condition changes. See if the problem is not due to water quality first of all (because unpleasant water conditions are the most common cause of exopthalmos, or accumulation of fluid behind the orbit, the condition often known as "pop-eye") and do water changes as needed. The same can be said for cloudy eye, though these have the same numerous causes, sometimes from malnutrition, irritation from the water, skin infections which cause hyperproduction of slime, etc. Here is a very good run-down of potential causes and treatments of pop-eye if improvement of water quality in itself does not help.

Q: My fish is growing an unknown lump or bump on its body, what is this?

This case in a congo tetra turned out to be an unusual case of Lymphocystis, a viral disease which causes small cauliflower-shaped tumors and usually doesn't respond to most medications (Courtesy of Tula of AofA).

The cause of this growth on a discus is still undetermined and may be either a spontaneously arising tumor or another type of infection (Courtesy of Mike of AofA).

A: Growths in fish have a large number of causes and are always difficult to diagnose. Here is a good differential diagnosis of these sorts of lesions with potential treatments.

Q: My fish is swollen and its scales are sticking out like a pinecone--what is this?

A bad case of dropsy in a calico fancy goldfish (Courtesy of JoAnne Burke).

A: For pictures of diseases, check my disease photo database. Look at the picture of dropsy, is this what you have? This is caused by fluid accumulating in the body cavity, a very bad sign of a tough internal infection. Sometimes there is nothing you can do about this, but in rare cases, improving water quality and/or an antibiotic will help. For more information on treatment of diseases, another great page to consult is FishyFarmacy.

Q: My cichlid has holes that are starting to erode away the pores in his head, what is causing this?

Small photo of HITH in an oscar; for the larger, clearer version, please check here (Courtesy of Adam of WorldCichlids).

A: This is a disease common in large, flat-bodied fish such as cichlids and gouramis, known in short as HITHD (hole-in-the-head disease). I am going to leave the full explanation of causative theories and potential treatments to a very good page on the disease by World Cichlids.

Q: Why does my fish clamp its fins (or starting to show fin rot) and stay on the bottom all day long, refusing to eat?

A: This is a not-so-good general sign of disease. Unfortunately, it is one of those things that is so general, you can't diagnose it right away just based on this, without more specific signs. Check the usual culprits (ammonia, nitrite) and see if those are out of whack before considering anything else.

Q: My fish has white/grey, stringy feces (poop), is this OK?

A: This is most likely due to some sort of internal infection of the gastrointestinal tract (commonly bacterial, sometimes parasitic). It's almost the equivilent of diarrhea. In many cases, it resolves on its own (just like it can in people) without medication... if it is eating and still swimming normally, I would just do water changes and leave it alone. If it comes with other signs like not eating and hiding all the time, consider quarantine and treatment with antibiotics.

Q: Why did my fish suddenly get these red streaks on its fins (or sides of the body?

Hemorrhagic septicemia from rising ammonia as seen in a marine yellow tang (Courtesy of Mark Delgrosso of ReefCentral).

A: This is known as hemorrhagic septicemia, and is due to a sudden stress (usually from adverse water conditions again, such as pH shock). It is especially common in overcrowded goldfish tanks, because they produce more ammonia than other fish (any level above 0 is toxic and can produce these types of effects. More info is found here.

Q: My fish is having trouble swimming upright, and frequently floats on its side and/or "twirls" in midwater, not able to get its balance--what's going on?

A: This is due to either trauma or infection of the swim bladder. An ominous sign in a new fish (more often the result of trauma for newly added fish, due to trauma in transit), these are fish you may not be able to save (Marcos has a good article on how to prevent stress caused by introductory shock here).

However, if you've had the fish for some time and it starts to do this, you may try antibiotics and a water change; if caused by infection, it is possible to cure. In fancy goldfish and "squat-bodied" fish, this is caused by a related but different entity commonly referred to as "swim bladder disease"--it may be due to infection, but may also be due to intestinal blockage/air trapping/constipation. Not feeding for a few days, and careful low-concentration treatment with epsom salt in the water may help; in the future, presoaked foods and feeding high fiber plant-based foods may help prevent reoccurence.

Q: I thought my water was the wrong pH, and I added pH up (or down) solution to it and tried to adjust it. But it never stays that way for long, and now my fish are looking sick. What happened?

A: If you are a beginner, I'd advise you NOT to try and adjust your pH, especially not this way. pH up/down solutions are pure acids and bases, and often won't work, depending on your KH (buffering capacity or carbonate hardness). If your KH is high, then you are performing a very futile experiment (much like an acid/base titration, only with living creatures in the solution that don't react well to it) and if it is low, your pH will swing rapidly. It's the pH "bounce" that can stress and hurt fish, not really being kept steadily at the same pH. Many fish are amazingly adaptable if given time, but if their bodies are asked to do it quickly, they will either be stressed or go into rapid and life-threatening pH shock. I advise beginners not to mess with pH adjustment, and to try and match their FISH to the WATER (in other words, find out your pH first, and then buy fish that do well in that range), not vice versa.

Also, there is no such thing as "perfect" pH, since different fish have different ranges of preference, and some are quite broad. 7.0 only means entirely neutral water, but this is not even necessarily the preference of many species, which may have ranges that center below or above neutral water, but cover a broad spectrum of tolerance. Trying to adjust pH can be necessary for the advanced breeder or keeper of hard-care species, but this should only be done by the experienced, and then with great care to watch all water parameters.

Q: I'm very confused, some people say that I should add salt to my FW tank, and some people say not to do it. Who is right?

A: This is a controversial subject with fishkeepers. I discuss pros, cons, and contraindications in my article, linked below:

To Salt or Not to Salt?

Q: Is it safe to put shells, (dead) coral, or rocks I found laying around in the tank?

A: With many freshwater tanks, the general answer is that it is not a good idea. Shells are composed of calcium carbonate, which will dissolve in soft to neutral water (the type of water many of our fish live in). It will gradually harden the water, as the ions go into solution. Many soft water fish (such as neon tetras), will not react well to this. Shells and corals are safe to use in a hard water or marine setting, however, because the buffering capacity (KH) of the water is already quite high, and they won't dissolve at the same rate; when they do, the ions contributed are ones that the fish prefer in the water anyway. Similarly, some rocks also contain substances that will gradually dissolve in the tank--limestone, for example, is also largely calcium carbonate. Some other rocks may contain impurities that also hurt your fish if you don't know their composition. The rule of thumb is to be safe rather than sorry, and buy only known aquarium-safe decorations; sometimes, collected rocks and materials can be boiled or put to the 'vinegar test' (if it fizzes with a little vinegar drop, it is not safe)--but this does not always work, because there are some things that dissolve very slowly and will gradually change your water chemistry over long periods of time.

Q: Why is the new driftwood I added turning my water brown?

Driftwoods can come from many sources, and some contain more organic material than others. The ones which still have organic material will still do some minor decomposition in the tank, and will gradually "leak" out tannic acid, the compound that turns water a brownish tea color. This generally won't hurt fish, and some soft water fish actually prefer the tannins, because it softens the water and simulates the natural environment of the Amazon River. However, excessive tannins are not always preferable, so boiling the wood in a pot of water until it runs clear (this may take many hours) before adding it to the tank may be a good idea for some of the more organic woods. Also, new carbon in the filter and frequent water changes will help keep the color clear.

Q: What is causing all this brownish-green film on the sides of the tank, the gravel, and the decorations/how do I get rid of algae?

A: Most likely, you are seeing diatoms, or brown algae. Algae problems most frequently occur where there are high nutrients--particularly nitrates and phosphates. The solution for diatom and most single-celled algae problems involve just more frequent water changes and decreased feeding. Also, there are products that will bind the nutrient compounds, such as phosphate sponges and Purigen bio-beads, which can be added to the filter. Reduced lighting may help in some cases, though not nearly as much as water changes (brown algaes can actually thrive in low-light conditions). Some of the multicellular hair and brush algaes are far more tenaceous and must be removed by hand or by vigorous pruning of plants. I do not recommend algacides for the tank, because though they will clear up algae problems, they frequently interfere with biofiltration and may risk causing a tank crash. Some bottom feeding fish will help some algae problems, but not all, and you should note that some "algae eaters" may not be appropriate for some tanks (plecos and clown loaches both grow close to or more than a foot long and need huge tanks!); these fish also do not eat all types of algae, need supplemental feedings to stay healthy, and may not do as good a job of algae control as you might expect.

Q: How do I clean off the white chalky deposits on the top of the tank without hurting my fish?

A: Obviously, never ever use soaps or toxic detergents (including undiluted bleach) in the fishtank. A good alternative for removing the white deposits (caused by alkaline calcium deposits, usually from tap water) is to try a a little white or apple cider vinegar. You can also try scrubbing the more stubborn spots with rock salt and an unused (soap-free) brillo pad.

Q: Why are my plants dying?

A: The most common cause of plant death in beginners' tanks is inappropriate lighting. This is much more common than inadequate fertilization, since fish wastes are in some cases enough to supply nutrients to the roots; lighting is an important limiting factor before fertilization and CO2 considerations. Most aquarium plants, contrary to myth, will not grow well under standard "cool" fluorescent lights that come with many hoods. Please read my article on planted aquariums for more details on lighting:

An Underwater Planted Paradise


At any rate, these are just a few of the problems that arise a lot with beginners. What do they all have in common? Almost all can be preventable if you stick to rules of cycling the tank beforehand, doing regular water changes (yes, when in doubt, a water change never hurts!), not overcrowding, not overfeeding, doing research on species-specific care (therefore minimizing stress), and quarantining new fish. Yes, sometimes fish DO just get sick, but hopefully we can prevent this from happening on a regular basis. Good luck!
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