info request.

450? do you mean 250 or 400?! they dont make 450 watt MHs for an aquarium
but to awnser your question, anything.... just not anywhere. like an acro obviously wouldnt do well if you had a single one over a 125 and put it way in the corner.

What size tank are you useing. 1 MH bulb will cove a 2 foot by 2 foot surface area. Provided you put things in that area you could keep softies,lps,sps, and clams. If it is outside that area I would say softies or nothing at all (except of course nonphotosynthetic corals). If your tank is more than 2 feet in length I would suggest puting as many halides as necissary as a half lit tank might look a little silly, but hey I have never seen one and you might be able to pull it off. Also I hope you realise how blue a 20000k bulb is going to be you may want to look into a 14000k or I do beleive that a 16000k is available.