The size of the elemental you can summon is always dependant on the available space (usually the low ceilings will get you). An exception to this rule is the canned elemntal, which can be popped open anywhere.Aside from that, you need resistance to mental attacks (and mayeb divine) that these sharks use ... that or run. And as always, look for a place you can better use to your advantage (i.e. only one or two sharks can see your party, but your whoel party can see those two sharks).
Tools for Wizardry(r) 7