will former damp wood attract termites?

I see from the pile of negative votes that this one is controversial.

It all depends on the type of timber. Some timbers can take a lot of damp before becoming good to eat.

Check that it isn't badly decayed (or it might fail). Get some polystyrene to sit the tank on while you check out the stand (avoids breakage). The easy way is to find a bit of the timber that looks bad but is out of sight. Use a strong knife across the grain to see if you can pull up a little splinter. If you can, it is fine, but if the wood just breaks without lifting a splinter, chances are that it has lost a lot of strength.

If the stand is OK, then you can give it some preservative and coat it with paint or varnish. Don't forget all the bits that don't show, especially the legs. For a fish tank, maybe use a metal primer instead of the preservative. Make sure every surface is sealed with the paint or varnish and caulk the joints. Termites ( & borers & ants) will no longer be able to detect the timber as good eating and they should leave it alone.

Termites do like their food slightly decayed by the right fungi. This makes it easier to digest and often a little more nutritious. Drywood termites will live in the timber and get by with whatever moisture is around. Subterraneans will typically travel between food and a water source. Dampwoods need their food already wet and usually obviously decayed.

Termites only attack dry and rotten wood. Carpenter ants however would love it.

Put the stand over a heater register if you have one for 3 or 4 days to dry out the wood completely.

Or in a window with the sun coming in...after the wood is completely dry sand lightly, prime and paint or sand lightly and refinish [ i used a great stain and poly mix, came out great and saved a lot of work]

keep the stand out of the cold and cover with plastic or oilcloth if you intend to put anything with water on it

There are dampwood and dry wood termites plus other kinds.