Frequent Aquarium Questions

• I have tetra fish and one is acting very strange. He's not swimming as usual, but he's not dead. The other fish will go down and visit. He responds to him but not when I tap on the window. Is it possible that it is getting ready to reproduce? What is happening?
  
  
• I have recently lost all but one of my fish (an algae eater) to disease. How long should I wait to put new fish in my tank or can I do a water change and add more right away. It has been 2 days.
  
  
• What causes fish to develop a concave stomach? I have guppies that this happens to ever so often, when it does they get very thin and eventually die.
  
  
• I "rescued" a 3" goldfish from my local pet store that has substantial damage (a chunk of flesh missing) to one side of its body. The fish also has "ich". I was told to treat the damaged area by placing the fish in one gallon of tank water mixed with two tablespoons of aquarium salt for five minutes every three days. Is this a proper course of treatment for the injury?
  
  
• My oscar has some sort of disease that is eating through his skin, putting holes right through him. It isn't affecting any of my other fish. What could it be and how can I treat it?
  
  
• I have 2 goldfish and one of them seems to be losing a lot of his scales. Other than that he appears healthy and lively. Is he ok? Is there anything I can do or will they simply grow back?
  
  
• I need to medicate my tank. How do I calculate the volume of water in my aquarium so I can dose accurately?
  
  
• Is it safe to use Maracyn with invertebrates?
  
  
• Should I be putting any medication in a 30 gallon fresh water aquarium to prevent any diseases?
  
  
• Does table salt promote healing from fin rot?
  
  

• I have tetra fish and one is acting very strange. He's not swimming as usual, but he's not dead. The other fish will go down and visit. He responds to him but not when I tap on the window. Is it possible that it is getting ready to reproduce? What is happening?
  
  No, the fish is not breeding. It is ill. The other fish "visiting" are simply exhibiting schooling behavior trying to keep the school together. We cannot advise on the illness without more tank information and information about the fish. We suggest you submit an aquarium support request to us.
  
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• I have recently lost all but one of my fish (an algae eater) to disease. How long should I wait to put new fish in my tank or can I do a water change and add more right away. It has been 2 days.
  
  After any incident of disease in an aquarium, whether fish loss occurs or not, is to wait a minimum of two weeks before adding any new fish.
  
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• What causes fish to develop a concave stomach? I have guppies that this happens to ever so often, when it does they get very thin and eventually die.
  
  There are several reasons why this can happen. The fish may be stressed or bullied and is unable to feed. Some internal diseases can cause this problem. A common problem with some species of livebearers like guppies and other species of fish is piscine tuberculosis, for which there is no cure. This disease causes the fish to waste away even though it may be actively feeding. This disease may also cause the spine to become malformed, sometimes called "bent-spine disease. This does not occur in all cases.
  
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• I "rescued" a 3" goldfish from my local pet store that has substantial damage (a chunk of flesh missing) to one side of its body. The fish also has "ich". I was told to treat the damaged area by placing the fish in one gallon of tank water mixed with two tablespoons of aquarium salt for five minutes every three days. Is this a proper course of treatment for the injury?
  
  If there is an open wound on the fish, that concentartion of salt could cause permanent tissue damage. Open wounds can get infected with fungus and bacteria, so the best treatment is to prevent those pathogens from growing and the wound will heal nicely.
  
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• My oscar has some sort of disease that is eating through his skin, putting holes right through him. It isn't affecting any of my other fish. What could it be and how can I treat it?
  
  This requires a very long answer because, unfortunately, this problem is not easy to treat and very little is known about it's cause. It is known as head and lateral line erosion disease, and it affects many species of freshwater and marine fish. In aquarium literature it is sometimes abbreviated to HLLE, LLE, or LLD (lateral line disease).
  
  The exact cause of lateral-line disease is unknown, though progress has been made. There are many theories, and a lot of research has been done on the subject. The April, 2003 issue of Aquarium Fish Magazine features a very good article by Jay Hemdal on HLLE. Possibilities include everything fom bacteria, viral agents, poor water quality, nutritional deficiencies, and so on.
  
  Rather than describing all of the possible theories, listed below are some great links on the subject (all open new pages):
  
  Hole in the Head - Lateral Line Erosion
  Head and Lateral Line Erosion
  
  The fish that are affected by this problem are usually laterally compressed such as Discus and Angelfish in freshwater and Tangs and Angelfish in saltwater. Oscars are also notorious for coming down with this disease. The problem is that the condition does not affect these species all the time. You can have one fish in one tank that develops HLLE and the same species in another tank that never gets it. You can even have two fish of the same species in the same tank and only one comes down with the condition.
  
  We recommend that you first start by making sure the water quality is good and that the fish gets extra nutrients in its diet. Do some good water changes, vacuum gravel and change filter media. Then get some fish vitamins and soak the food in them before feeding. Try this for about six weeks and see if the problem clears up. In our experience, this works in about 50% of the cases we've seen. If that does not work, we suggest you return to this page and explore some of the treatments that are described in the pages to which the links above will take you.
  
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• I have 2 goldfish and one of them seems to be losing a lot of his scales. Other than that he appears healthy and lively. Is he ok? Is there anything I can do or will they simply grow back?
  
  Scale loss is almost always caused by injury, due to fighting with other fish, or from hitting sharp rocks in the tank. Goldfish do fight, so watch the one that isn't losing scales! Also keep an eye on the one that is losing scales, and make sure he isn't scratching up against the rocks. That could be a sign of a parasite like "Ich" which looks like little grains of salt on the body and fins.
  
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• I need to medicate my tank. How do I calculate the volume of water in my aquarium so I can dose accurately?
  
  Step 1) Using the inside dimensions of your tank in inches, measure the height of your aquarium only up to the water line, and use this as the height in the formula: length x width x height divided by 231 to obtain the approximate gallons of water in the tank.
  Step 2) Estimate the total combined weight in pounds of all the gravel, rocks, coral and other decorations in the tank. Divide this total weight by 8.3 (A gallon of water weighs approximately 8.3 pounds), and subtract the result from the volume in Step 1. This is a good approximation of the number of gallons of water in your tank. This is useful to know when you are using strong medications with a high risk of an over-dose, or if you dose your reef aquarium or live-plant tank with nutritional supplements. Incidentally, we do not recommend using most fish medications in any aquarium, and we definitely do not recommend using any medications in a living-reef marine aquarium. Set up a hospital tank. You'll be glad you did.
  
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• Is it safe to use Maracyn with invertebrates?
  
  No, we do not recommend the use of ANY antibiotic, including Erythromycin, although Mardel Laboratories may claim their product is safe for use with invertebrates. If you are treating cyanobateria (slime algae), then we suggest using a product designed for that purpose. If you suspect a bacterial infection in your fish, you should set up a quarantine tank and treat them separately. You may provide complete details about your situation to our email support staff at http://www.aquariumpros.com/features/email.htm and we will try to help you.
  
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• Should I be putting any medication in a 30 gallon fresh water aquarium to prevent any diseases?
  
  It is not a good idea to use medications on a constant basis to prevent disease any more than it would be a good idea for you to take medicine to prevent you from getting sick. The continual presence of medicine in the water can be very stressful for fish. It is OK to use a small amount of aquarium salt in the water (a teaspoon per ten gallons), but make sure that none of the fish you have are sensitive to salt and don't use salt if you keep live plants.
  
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• Does table salt promote healing from fin rot?
  
  I would not use table salt, which can conmtain lots of iodine and lacks many trace elements including potassium. I would use regular aquarium rock salt, and yes, it does a great job of promoting healing in any external injury or disease, provided the fish in the tank are not too salt-sensitive. Salt should be added slowly to the tank in a solution form dissolved in water. Typical dosage is a tablespoon per ten gallons.
  
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