Question
"How do I know if there is too much algae in an outdoor fish pond or pot?" tracks the potential issues with too much algae in my fishes environment.
I keep goldfish outdoors in large, ceramic pots, approx 50 cm in diameter x 80 cm tall. The pots contain pond weed, and there is some algae on the inside of the pots, but it hasn't seemed to bother the fish up to this point.
I have been considering purchasing snails from the local fish shop (aquarium, not fish and chip shop :) ). I have a some concerns:
Do I get more than one snail per pot? The overabundance of snails is addressed by "What are some effective non-chemical methods for controlling the snail population in an aquarium?"
Will the snails eat the algae and not the plants?
What attributes should I look for in the snails I purchase for my particular type of setup?
Answer
Your pot has, more or less, 60 liters of water, so I'll make some analogy with a 60 liters aquarium.
1 - If you're purchasing the snails, I assume that they are those desirable, pet snails, which tend to be bigger (from 2 up to 3 inches). So one would be enough.
Although most snails are hermaphrodites, they need to mate to reproduce. So, having just one snail would prevent that overabundance
Some snails, like apple snail, have separated sexes, so you could have more than one if you choose only males or females. And males would be more desirable, because females can store the sperm from a previous relationship for months, and perhaps the fish store might not know about her past. :)
2 - Snails, in general, will eat your vegetation. Depending on the plants you have (like softer ones), they will prefer to eat plants instead of algae, and might have the opposite effect than you planned.
Answered By - woliveirajr