Sea life centre - Southsea

It does cost a bit to go in, try to angle for student discounts.

They have all types of fish; exotic marine (clownfish, lionfish, sea horses) also octopus, rayfish, larger sea fish, otters and a chameleon, frogs, lizards. It might be worth calling them first to check the creature you want is there.

Blue Reef Aquarium,
Clarence Esplanade, Southsea, PORTSMOUTH,
Hampshire, PO53PB   
Tel: 02392 875222

 

Cumberland House - Southsea's Natural History Museum

Cumberland House Natural History Museum
(Eastern Parade, Southsea, adjacent to Canoe Lake. Free Admission)

Some examples of taxidermied animals can be found here (upstairs) as well as live fish, crickets, there's also a butterfly house at the back (although they're asleep at the moment).
There are quite a few birds on view, also a fox, mice, rabbit, badger, weasels, seals and insects.