Pike cichlid not eating, hiding. Could my 20-gallon tank be too small?

Cichlids in general are quite aggressive. If you have two males, this may compound the aggression. Tou can add some more plants and cover to provide hiding spots. If that doesn't work, a larger tank may be indicated. If a larger tank doesn't work, you may need to keep the aggressor separate.

Check the water temperature. Low temps can affect appetite and digestion in fish. Angels do best between 78 F and 80 F. You can soak food in garlic juice to stimulate his appetite. Next, check the water chemistry. This can be done using a home test kit or by submitting a water sample for testing. Most pet stores will do this for free or for a small fee. Confirm 0 ppm ammonia and nitrites with nitrates at 40ppm or less in a tank with live plants or 20 ppm or less in an unplanted tank. Partial water changes can be done, if indicated, to stabilize chemistry and/or maintain water quality. use only aged or conditioned water that is temperature matched to prevent stress or shock. Although they do best in slightly acidic and soft water, they are quite adaptable. Fast him for 2-3 days then feed bits of cooked and shelled green peas. if he is constipated then this should him him get regular again. A broad spectrum parasite medication, such as PraziPro, should be considered. You can find it in the aquarium section of the local Petco. Follow label directions carefully.

Check the water temperature. This species does best between 68 F and 77 F. Low temps can affect appetite in fish. He may be near the heater for warmth. Check the water chemistry as well. Use a home test kit or submit a water sample for testing. Most pet stores will do this for free or for a small fee. Aim for 0 ppm ammonia and nitrites with a nitrate level of 20 ppm or less. Partial water changes can be done to stabilize chemistry if indicated. Use only aged or conditioned water that is temperature matched to prevent further stress or shock. If it is a "new" tank, there may not be enough food/algae on the bottom for it. Use sinking pellets or toss in some vegetables or greens. Be sure to remove any uneaten food after 24 hours to prevent it from fouling the water.

This could be due to having a tank that is too small. 6 goldfish in one tank poses several potential issues. Ideally, 1 fish should have a 20 gallon tank with an additional 10 gallons provided per extra fish. This would mean they should be in at least a 70-75 gallon tank. The reason being goldfish produce a larger than average bio-load (wastes) that can quickly overwhelm a small tank and filter. Poor water quality can lead to stress and infection as well as behavioral issues. Depending on their sizes, the present tank could be overstocked leading to bullying and fin nipping. Check the water quality and chemistry. Use a home test kit or submit a water sample for testing. Most pet stores will do this for free or for a small fee. Aim for an absence (0 ppm) of ammonia and nitrites with a nitrate level of 20 ppm or less. Perform partial water changes, if indicated, to stabilize chemistry and maintain or improve water quality. Use only aged or 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 (18.3 - 22.2 C). Make sure the filter is rated for at least twice the volume of the tank. If possible, separate out the aggressive goldfish to a different tank to prevent further bullying and injury.

Separate her out into a hospital or quarantine tank. Bump the water temperature up to about 80 F. Examine her for signs of illness or injury including damaged fins, parasites, dark or red spots or bloating. Add an air stone to increase oxygenation. Without a specific cause, general treatment with salt would be recommended. You can add 1 teaspoon of plain aquarium salt (NOT table salt) per gallon of water to the hospital tank. The easiest way is to dissolve it in some tank water then gently pour it in. Salt aids healing, reduces stress, promotes a healthy slime coat, improves gill function and can treat several parasites. Treat for 10-14 days then perform partial water changes to decrease salinity. If this does not help, consider a broad spectrum antibiotic or antifungal medication based on symptoms. You can purchase either online or in the aquarium section of most pet stores. Read package directions carefully before use.

Remove them or provide more cover (plants and hides) for the other fish to hide or escape. When fish hang near the top, it is usually due to low oxygen levels, low water temperature or improper water chemistry. It could be related to the different filter or the water change. Confirm proper water temp and use a test kit to check water chemistry. Ammonia and nitrites should be at 0 ppm (parts per million) and nitrates should be 40 ppm or less. Monitor chemistry closely until you know how the new filter operates. Make sure it is rated for the size tank you have to ensure adequate filtration. Correct imbalances using chemical treatment and additional partial water changes using aged/conditioned water.

Thanks for reaching out about Grandfish. If the water quality (pH, ammonia, nitrites and nitrates) have been tested and normal, other considerations should be considered. Intestinal parasites or infection, liver or kidney disease, a gastrointestinal obstruction are just a few of the possibilities. A veterinary visit is recommended to assist with a diagnostic and treatment plan. Good luck.