My fish are dying! Why are my goldfish and angelfish dying in my tank?

The fish pictured are incompatible in the same tank. Angelfish (black ones) are tropical fish and do best in temps between 73 F and 84 F. Goldfish (white and orange) are cold water fish thriving in temps between 65 F and 72 F. It also appears as if one of your angels has some damage to a tail fin. This is typically due to fin nipping by other fish. You will need to remove either the angels or the goldfish and place them in a different tank. Check the water chemistry for elevated levels of ammonia or nitrites. This can occur in an uncycled tank or a tank that is overstocked. Partial water changes (30-50%) daily can decrease toxin levels. Use only aged or conditioned water that is temperature matched to prevent stress or shock. Confirm your filter is rated for at least twice the water volume of the tank, especially for the goldfish. The links below provide additional information for care of angels and goldfish. http://aquariumtidings.com/angelfish-care/ http://aquariumtidings.com/all-about-goldfish-how-to-care-for-a-goldfish-fish-at-home/

Check the water chemistry and temperature. Use a home test kit or submit a water sample to test fro elevated ammonia or nitrite levels. Most pet stores will do this for free or for a small fee. Partial water changes can be done, if indicated, to stabilize chemistry and improve or maintain water quality. Ideally, you want 0 ppm ammonia and nitrites with nitrates at 20 ppm or less in a non-planted tank or 40 ppm or less in a planted tank. Use only aged or conditioned water that is temperature matched to prevent stress or shock. You'll need to keep the temp at the upper limits for Red Tails in order to keep the Angelfish comfortable. That would be in the 78F to 80 F range. Both have similar pH requirements, 6.8 to 7.5. You can fast the Angel for 2-3 days then feed bits of cooked, shelled green peas. This will usually resolve constipation and bloating. Pristine water quality may resolve the patch on your shark. Recommending a medication without more information or a clear image would be risky to the stability of the tank's nitrogen cycle. You can use plain aquarium salt (NOT table or Epsom salt) as a general tonic. It will reduce stress, improve gill function, may treat minor infection and aid in recovery. Dissolve 1 tablespoon per 5 gallons of water in a cup of tank water and gently pour it into the tank. Treat for 10-14 days then reassess the condition. A note on tank size: Although the two fish may be fine in a 15 gallon tank now, you will likely need a larger tank as they mature. Red Tails can reach 6-7 inches and Angels can reach 6-8 inches. At adult size, a 15 gallon tank will be insufficient and could lead to some aggression from either fish.

I'm sorry you are having difficulties with your aquarium. There are several issues that should be dealt with right now. They are water chemistry, aquarium size and choice/number of fish. Any new aquarium should be set up and, ideally, run empty for several weeks (usually 4-6 weeks). This is so beneficial bacteria have an opportunity to populate the substrate and filter. These bacteria are necessary to break down wastes that fish will produce. The technical phrase for this is "establishing the Nitrogen cycle". These bacteria will break down wastes into ammonia then nitrites then nitrates. Nitrates can then dissipate or be absorbed/used by live plants. In high enough concentrations, ammonia and nitrites are toxic and can kill fish. Cycling a tank with fish is possible but it increases the risk of loss. Water chemistry should be checked every few days using a liquid home test kit. A water sample can be submitted for testing , but is not as convenient as testing yourself. Most pet stores or fish stores will do this for free or for a small fee. Partial water changes, no more than 30%, can be done as needed to stabilize chemistry and maintain water quality. Choices for water conditioners include NovAqua, AmQuel Plus, Prime, StressZyme or StressCoat. Tank size is another concern. With most fish, the widely accepted "one inch of fish per gallon" will be sufficient. For koi and other carp species, including goldfish, the rule is not sufficient. At full size, goldfish need 20 gallons per fish with an additional 10 gallons for each additional fish. Koi do best in larger tanks, much larger...we're talking in the hundreds of gallons or small ponds. These species produce a larger than average bio-load (wastes) that can quickly affect water quality in a tank. To combat this, large water volumes and powerful filtration are required. Any filter should be rated for at least twice the tank volume. I'm not sure what size tank you have now, it may be fine if the fish are young and small, but they will quickly outgrow it. The last issue is choice of fish. Koi and goldfish are cold water fish. They do best in water between 65F and 72F. Most species of sharks do best in the high 70sF to low 80sF. Keeping fish in incorrect water temperatures will lead to stress and illness. This could be compounded by the water quality/chemistry issues you are having currently. Until the chemistry is stable and water quality is maintained, your fish will continue to become ill and possibly die. Any treatment will not be successful in this situation. Do not purchase or add any more fish until the tank has cycled. If you have additional questions, you can post them in the forum or request a consultation to discuss the case in greater depth.

Loss of color in fish can be a sign of severe stress. Stress can be brought on by disease, poor water quality, over cleaning the tank (too frequent or too large water changes), over aggressive fish, poor or inadequate nutrition, being moved, over crowding, and a host of other situations. I recommend that you start by reviewing your water quality and tank environment. How are your water parameters? Review how often you do water changes and how much water you change at one time. How much are feeding? Could you be over or under feeding your fish? Is there a bully fish in your tank - a fish that chases or aggresses against other fish. Are the number of fish in your tank suitable for the size of the tank? Look for signs of disease. Fish can suffer from bacterial, viral, fungal, protozoal, and parasitic infections, but not all species of fish suffer from the same illnesses. You can find charts of fish diseases in books or on the web to help you narrow down what illnesses might be affecting your fish. Treatment of disease will be based on determining what type of organism is making your fish ill. To prevent illness in fish, maintain high water quality, avoid over crowding your tank, and quarantine new fish before introducting them to your tank.

I am so sorry that you are having this problem! With multiple die offs of fish, one of the first things to consider is that the water quality may need to be addressed. I didn’t see you mention in your post whether you have been able to assess that or not, but it would definitely be something to evaluate. Things like high ammonia, high nitrites, and high nitrates can be devestating for fish. Also, if your filters are not working properly, or are not in the correct set up, that can also contribute to fish death. From the clarity of your water and the lack of substrate and tank furniture, it makes me more suspicious of this contributing to your issues. The other major reason for multiple fish deaths are infectious diseases (bacteria, parasites, fungus) - but ideally these would be diagnosed by a veterinarian. There are many over-the-counter medication treatments at pet stores for these, however they can be damaging to your water system, so ideally would not be used unless you know the problem that is going on.

Check the water chemistry using a home test kit or submit a water sample for testing. The local Petco may do this for free or for a small fee. Aim for an absence (0 ppm) of ammonia and nitrites with nitrates at 20ppm or less. Perform partial water changes to stabilize chemistry and/or to improve water quality. Rinse the filter media in tank water, not tap water, and replace it. Use only conditioned water that is temperature matched to prevent stress or shock. To limit algae growth, maintain pristine water quality via filtration and regular water changes. If possible, turn up filter flow to keep water moving. If this stresses the fish though, do not do it. Do not overfeed and remove any uneaten food promptly. Limit lighting to 8 hours daily and closely monitor water temperature as well. All these can promote algae overgrowth.

A 5 gallon tank is insufficient for goldfish. They produce a larger than normal bio-load (wastes) that can quickly overwhelm a small tank. Ideally, one goldfish should be in a 20 gallon tank with an extra 10 gallons added per additional goldfish. The filter should be rated for at least twice the volume of the tank. They are likely succumbing to ammonia and/or nitrite toxicity. If you test the water, it is likely both parameters will be dangerously high. Perform a 50% water change. Use only conditioned water that is temperature matched to prevent further stress or shock. Goldfish are cold water fish and do best between 65 F and 72 F. Plain aquarium salt, NOT table or Epsom salt, can be used to reduce stress, improve gill function and aid in recovery. Dissolve 1 teaspoon per gallon in a cup or two of tank water and gently pour it into the tank. Treat for no more than 14 days then perform a partial water change to decrease salinity. A 5 gallon tank would be appropriate for one male Betta or a small school of Neons (3-5).