I have a 5 USG tank and 3 Gold fish... one is black moor... she got her eye hit lately and skin is hurt and getting red in about 25% of one eye... how can I medicate this, knowing that ambient temperature is almost 25 celcis... I just relaized that the tank is small so I plan to replace it with a bigger one.
Many thanks indeed for your open door
The aquarium is much too small for three goldfish. The redness is from ammonia burns which is going to build-up in an overcrowded aquarium. Goldfish have a very high bio-load, which basically means they produce ALOT of waste. This is because they have no stomach's so anything that they eat literally passes right through.
Your Black Moor is a fancy goldfish here's something to determine the species of your other two. If the other two are common's I suggest donating them to a local pond or petstore as they will get very large and will be a bear to keep in a aquarium.
Common goldfish get 2-3 feet and two would need a 100 USG aquarium with double or even triple filtration. With religous water changes. You can tell if they are common goldfish because they are longer more torpedo shaped then fancy goldfish.
Fancy Goldfish get 6-8 inches and 3 would fully stock a 55 USG aquarium with double filtration. They are rounder more ball shaped they anything and have stouter longer fins.
Medication at this point would be irritating to the other tank mates. There is no cure for ammonia burns. A larger, cycled tank is what these goldfish need. Good water quality will take care of any sores or injuries. It will easily get infected in a dirty ammonia filled aquarium.
25 C is a high 76 degrees in F degrees. That is tropical temperatures. Goldfish are coldwater fish. If you have a heater I would slowly, over a week of time, lower the temperature to nothing. Then when the heater has cooled for several days, remove it. The heater must cool before it is remove otherwise it will crack.
Try getting and cycling a bigger aquarium as soon as possible so bacterial infection won't happen. Do not medicate you will just irritate your other goldfish.