Most of their stock is "bread and butter" fish, but there are some less common corys like "Venezula black" and adolphoi amongst them. Their tropical highlight is a group of four of those newly introduced archerfish (bit out my price range), Toxotes blythii, but I was pleased to come away with what appeared to be some ~4cm baby Synodontis decora (no sign of Valentino hybrid markings) at the weekend. The staff are pretty enthusiastic at World Of Water.
For more of an all round mix of less common fish in the hobby, it would be well worth the trip over to Aquajardin in Fairoak (~25 minutes drive from Romsey), where you might get tempted to buy some ~4cm Bearded Cory for £20 each; a huge range of catfish; Dragon Gobies etc.