Other than that, no, as long as you take some precautions. Limit the amount of current so that the fish aren't run to death. Lake fish and those from slow moving bodies of water shouldn't be kept in high current tanks. You can limit the current by using a diffuser on the return or running the water through a filter sponge.
Agreed, but you are limited by how much water your tank can drain. A 1" drain can only handle about 600 GPH, so a pump stronger than that would run the sump dry quickly.
The rule of thumb is to make sure your drains outpace your pump -- you can only pump back that which drains, so you can run LESS gph than your drains will allow, but you can't run more.
So, you have to determine the total drain capacity first and THEN select a pump.
No worries...... I wasn't disagreeing with you, but the question was indicative of someone new to the issue of "sumps and pumps," and many people make the mistake of buying the sump-pump without knowing the limits of their drains. Just trying to save him some headaches.
Perhaps you were speaking in general terms, whereas I was considering the specifics in the title of the thread.