The quick answer is yes. The longer answer is yes, but anytime you put two "peaceful" crabs together something could go wrong. Let's say as a for instance - the dominant one of the two different species doesn't get enough to eat. He could prey upon the weaker one and consider it food. So, what does that mean and what would I do? If I wanted to get a SLF and an EC, I'd take the chance. Because chances are they will be fine.
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