Hi
,
Orandas need a minimum of 30 gallons of water per fish. Four goldfish + a pleco in that small a space are producing an extreme amount of waste that is definitely leading to water toxicity, which is what I initially thought when I mentioned ragged fins. Here are my suggestions, based on my personal experience with goldfish:
1. Get a larger tank ASAP. The pleco really needs to find a new home. He's a warm water species and goldfish are coldwater species. Plecos have a tendency to suck on the slime coating of goldfish. Plecos can also grow to 12+ inches and produce LARGE amounts of waste. The sooner you can find him a different tank or a new home, the better for everybody.
2. If you can't get a larger tank, buy a plastic tote (200 liters or more). These are inexpensive and, if you put a good filter and airstone in, can house at least 2 of your goldfish happily for a time. Three goldfish in the tote, two goldfish in the tank, no pleco, and you'll have much, much happier fish all around.
3. Get an API water test kit. They're considered the most reliable test kit on the market.
4. Find some Prime water conditioner. This will help protect your fish from the effects of the toxic chemicals in his water.
5. Until you can do all of the above, change 50% of the tank's water immediately using whatever water conditioner you currently have on hand, wait no more than two hours and then change 50% more. Because you are so overstocked, I would then recommend a minimum of 50% water changes every single day.
I know this all sounds overwhelming. I have 2 goldfish myself which require 100 gallons of water each. I initially had no idea of their needs and was shocked to find out when they start getting sick that they couldn't live in a 10 gallon.
The thing is, fancies can grow to 8+ inches. Look at this visual:
http://www.aquariumadvice.com/forum...uire-big-tanks-visual-perspective-265871.html
Keeping them in too small a tank leads to stunting, meaning that their outsides stop growing, but their insides don't, leading to a slow, painful death.
Feel free to ask as many more questions as you have. Everybody here will be happy to help you.