Hiya, I normally try not to get involved in stocking ideas as it's all down to personal choice but as I know your in the same neck of the woods as me and are more than likely to have very soft water like the rest of us in these parts I'll recommend you have a look at soft water loving fish as it's always best to stock for the water you have naturally as try to force a fish to live in conditions it's not built for.
I know nothing of paradise fish as I've never kept them so I've no idea of their requirements in water conditions.
I can though, give you a list of soft water loving fish. This will then set you off on a path of research. I can also recommend that you arm yourself with the odd fish book. These can be great to flick through. I picked one up in the pet shop at Otley called Mini Encyclopedia - The Tropical Fish Guide by Gina Sandford. It's not a bad little book to be honest and seems to be readily available. There's some nice colour pictures inside along with descriptions of each fish and it's 'ideal conditions'. I've also picked up a couple over the years in charity shops so keep your eyes open for them popping up if your a bargain hunter
Okay. On to a list of soft water loving fish
All tetras - neons, cardinals, emperors (they can be really colourful with bright purple bodies and yellow fins) the list goes on and on for tetra's - too many different species to list. Do your research though as some are peaceful and great for community tanks, others can be nippy to a little aggressive.
Harlequin Rasboras - a lovely small fish, best in a large shoal. Again research as there are different types. I have some lovely dark blue ones with a gold head and gold fins
Corydoras - probably the loveliest fish I've ever had. Peaceful and fun with a sweet nature. Keep in groups 5-6 of the same type. Some types are smaller than others. Panda's and pigmys being the smallest two that are always readily available
All South American Cichlids - angelfish, rams, keyholes, again too many to list and some need to be approached with caution as some can be aggressive, others are peaceful and shy. Lots of research before buying with them.
Gourami's are another that will be okay in soft-ish water but beware of the dwarf gourami as it's been known lately to carry a disease that is incurable
Barbs - in general okay in soft water but a lot can be nippy. A nice colourful one that isn't nippy is the Cherry barb. They stay quite small and the males are lovely bright red. They will need a group though to be at their best.
Hopefully I've set you off now on a journey of discovery.... happy fish hunting
