My panda moor goldfish has some red spots on it's pelvic fin and just in front of it's back fin. i know my tank is over crowded. It's new to the tank (4 days).

Sounds like ammonia burns. Moors and other goldfish need 20 gallons for the first and 10 gallons for each additional goldfish. They get 1 foot long and live 30-40 years as an average lifespan. They don't grow to the size of there tank. They become stunted from poor water conditions

Comet and Common goldfish get 2 foot long and need 75 gallons+ for any amount. Same lifespan and same thing for "growing to the size of there tank" You need to do a 50% water change ASAP and give us your water parameters *Ammonia, NitrITe, NitrAtes,* You want Ammonia: 0 NitrItes: 0 and NitrAtes: as low as possible. No more then 20. Goldfish are actually carp. Get very large. And don't have a memory span of 3 seconds. They are actually intelligent carp.


Edit: Don't put all those chemicals in the water as suggested by another user that do nothing but prolong the issue. Water changes are the only real way to get rid of Ammonia.

Red is usually injury from other fish or more likely due to bad water quality and ammonia or nitrite poisoning. The fish is okay but you need to hurry and check the water quality. If you have an overcrowded tank feed better food pellets that float, increase the filter volume by a bigger power filter or add another air stone bubbler. Do small water changes after you test the water. Kordon rid fungus is good for treating the whole tank, anything it has or doesn't have it is too late after water to water contact. It may not be sick it may most likely be bad water quality issue! Fancy goldfish should be with mellow fish and never chinese algae eaters which munch on them, or tiger barbs or cichlids.

The Importance of Cycling an Aquarium and only doing small water changes so that you do not upset the biological balance: pets question and answers,www.5d2d.com
I have raised fish for more than 35 years, the most common hardship that people face when raising pet fish or pond fish is due to not understanding the importance of the Nitrogen Cycle and Cycling the aquarium or fish pond. It is extremely important to gradually add fish that get along to any aquarium. If you just did more than a 50 percent water change then the aquarium or pond needs to be cycled again and the water quality parameters of Ammonia and Nitrite monitored. Never change the pH suddenly it is fatal or near fatal. Always remove the chlorine,chloramine and add water that is the exact same temperature so that there are no sudden temperature changes on the fish.

Monthly water changes of 10 to 20 percent are recommended, in some instances it should be done weekly. Always monitor the Ammonia and Nitrogen levels and add beneficial bacterial enzymes if needed, usually they are needed and can be purchased. BIG WATER Changes of over 30 percent can actually do more harm then good, and upset the balance.Overcleaning of the gravel and tank is a fast way to kill off the fish you have raised for so long.The beneficial bacterial colonies live on the surfaces of the filer material,gravel,rocks,plants,etc! pets question and answers,www.5d2d.com

Green algae means that the water quality is in balance. Green algae looks bad but is beneficial. Reduce the lighting number of hours and keep away from a bright window.Reduce the lighting to around 8 hours daily;use a coffee pot timer if needed. Algae will first occur as a brownish film then gradually green up, at that time you can also add an algae eater or snails of appropriate type. Do not kill off your pleco or otocinclus by putting it in the tank too soon!

When you are ready I suggest a heated smaller aquarium as a quarantine tank for new arrivals for two weeks, then add them to your main aqaurium. Water should be cycled in both aquariums. I also highly recommend sponge filters maintain beneficial bacterial colonies. New fish should be monitored for possible ick and fungal infections, these can be frequently seen in fish from large pet store chains and stores which sell fish and linens and more. Stores that sell clothing and fish etc tend to be clueless as to what they mix in the same tank. One of the worst examples of this was male fancy guppies in a tank full of spotted green puffers. Not only do those places have low quality fish care but they are expensive. pets question and answers,www.5d2d.com

My favorite products are Aquarium Salt (non Iodine salt used for water softeners,ice cream making or sold for freshwater fish),Kordon Rid Fungus which also works great on Ich. Low level doses of Malachite green. Scaleless fish like tetras,catfish,ghosts,silver dollars, loaches,botias should be treated with scaleless type medication or reduced levels. Do not use copper products on snails,shrimp,or crustaceans.Antibiotics should only be used when there is a bare bottom aquarium and the water quality is being checked. Many bad water quality issues can trigger bacterial and fungal issues, and antibiotics are not always beneficial. They tend to also destroy the water quality.