Selcon is a mixture of essential fatty acids and some vitamins thrown in for good measure. It is often used to "coat" adult brine shrimp (they ingest it as well) as a way of getting more nutrition into fish as adult brine shrimp aren't very nutritious on their own (kind of like popcorn versus a granola bar). If you coat the food you are feeding to fish, with selcon, it is a good way of helping to boost their immune system in order to fight off any infection they might have as well as promote faster healing.
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Kent Zoe works much the same way although it doesn't contain the fatty acids.
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