Expert: Susan Fields - 11/3/2009

Question
we just got a black moor. we have a 5 gallon tank with a filter and also have a goldfish. The pet store assured us that it was ok to put these 2 together. However after reading on the internet does not sound like we did the
best thing. Anyways, the black moor has developed a white spot on the outside of his eye (on the skin-for lack of a better description). Any idea what is going on. Please help this is our first attempt to own fish. BTW _ we used tap water to fill the tank and ran the filter for 24 hours before we put the fish in their.  

Answer
Hi Erica,

The black moor and other goldfish likely will be fine together. As long as both types are getting their fair share of food and no one is bullying anybody.

The white spot may be nothing. Its too early to tell much at this moment but keep an eye on it and notice if it changes in appearance or size. A picture would be helpful if possible.

The main concern I would have is maintaining good water quality with a small setup like a 5 gallon --which can quickly get polluted and miserable (even with a filter) with messy creatures like goldfish. While many sources still recommend keeping goldfish in small setups and even bowls its not the best thing long-term. Goldfish grow large, need space to swim and exercise and pollute their water quicker than most other aquarium fish.

With a small setup like this. I would recommend changing at least 30-50% every other day using a gravel vacuum to siphon waste on the bottom ((making sure the replacement water is treated with a water conditioner and the temperature is equal to or just a bit warmer than your aquarium's)).
*This is trouble, but its best for the goldfish to have clean water like this. It would be ideal to upgrade to at least a 10-gallon or better yet a 20-gallon. Fish suitable for small setups like 5-gallons are bettas, tetras, and other small tropical species. They would need a heater though, unlike goldfish.

New aquariums also must establish a "biofilter"  which is special good bacteria that control the ammonia the fish produce. They are not yet established in a newly setup aquarium so one must take extra caution towards making sure the water is safe until the bacteria can establish...which usually takes about 4-6 weeks, since ammonia is very toxic to fish.
You can also test for ammonia and other levels with a simple test kit from your petstore.

I really hope this helps and best of luck!
Karen~