scubadoo
Fish Crazy
scubadoo, Where is the World of water store
Its at Blooms Garden centre (used to be known as Jardiniere) near St Mellons on the old A48 Cardiff-Newport road. Its nowhere near as big as the MA shop, but they do sometimes have a nice selection of fish and I've found that their prices are a bit more competitive - particularly on invertibrates. I got some more amano shrimp a couple of weeks ago at £5 for 3.
Maidenhead Aquatics also have another branch at a garden centre in Wenvoe but I haven't been there - its supposed to be smaller than the one at Pugh's.