This short guide covers which common fish are suitable for your size tank.
18" - 46cm
Aphyosemion australe - Cape lopez lyretail
Betta splendens - Siamese fighting fish or betta
Carinotetraodon travancoricus - Dwarf or Pygmy Puffer - Species tank only! One for every 4 gallons
Danio margaritatus - Celestial Pearl danio or Galaxy rasbora
Corydoras panda - Panda cory
Hyphessobrycon herbertaxelrodi - Black neon tetra
Paracheirodon innesi - Neon tetra
Poecilia reticulata - Guppy
Puntius titteya - Cherry barb
Others
Killifish species
Microrasbora species
Betta species
Dwarf corydoras species
Boraras maculatus
Ember tetras
Sparkling gouramis
Honey gouramis
24" - 60cm
All of the above
Colisa lalia - Dwarf gourami
Corydoras adolfoi - Adolfo's cory
Corydoras aeneus - Bronze/Albino cory
Corydoras trilineatus - Three-line cory
Gasteropelecus sternicla - Silver hatchetfish
Gymnocorymbus ternetzi - Black Widow tetra
Hemigrammus caudovittatus - Buenos aires tetra
Hemigrammus erythrozonus - Glowlight tetra
Hyphessobrycon eques - Serpae tetra
Iriatherina werneri - Threadfin rainbowfish
Macropodus opercularis - Paradise fish
Melanotaenia praecox - Neon rainbow
Nannostomus marginatus - Dwarf Pencilfish
Otocinclus affinis - Dwarf otocinclus
Otocinclus vittatus - Oto
Paracheirodon axelrodi - Cardinal tetra
Barbus pentazona - Pentazona barb
Puntius tetrazona - Tiger barb or Moss green barb
Trigonostigma heteromorpha - Harlequin rasobra
Others
Glowlight danios
Dwarf danios
Corydoras Sterbai - Sterbai cory
30" - 75cm
All of the above
Ancistrus sp - Bristle-nosed catfish
Apistogramma agassizii - Agassizi's dwarf cichlid
Apistogramma cacatuoides - Cockatoo dwarf cihlid
Apistogramma macmasteri - Macmasters dwarf cichlid
Corydoras paleatus - Peppered cory
Danio rerio - Zebra danio
Microgeophagus ramirezi - Ram cichlid
Puntius conchonius - Rosy barb
Puntius nigrofasciatus - Black Ruby barb
Puntius semifasciolatus - Golden barb
Xiphophorus species - Swordtail
Xiphophorus species - Platy
Others
Kuhli loach - Panio species
Pearl danios
Danio rerio var. frankei - Leopard danios (Spotted morph of zebra danios)
Danio roseus
Danio kyathit
Clown pleco
Hillstream loaches - Need specialist care
36" - 90cm
All of the above
Crossocheilus siamensis - Siamese algae eater Should be at least 16" wide
Epalzeorhynchos bicolor - Red-tailed black shark Should be at least 16" wide
Epalzeorhynchos frenatum - red finned shark Should be at least 16" wide
Epalzeorhynchos kalopterus - Flying fox Should be at least 16" wide
Hyphessobrycon erythrostigma - Bleeding heart tetra
Melanotaenia lacustris - Lake Kubutu rainbowfish
Melanotaenia trifasciata - Banded rainbowfish
Pelvicachromis pulcher - Kribensis
Pterophyllum scalare - Angelfish Tall tank needed
Trichogaster leeri - Pearl gourami
Others
Skunk botia - Aggressive!
Horsefaced loach
Upside down catfish
Western rainbowfish
Congo tetra Should be at least 16" wide
Yellow congo tetra Should be at least 16" wide
Brochis splendens
48" - 120cm
All of the above
Aequidens pulcher - Blue acara Should be at least 20" wide
Botia almorhae - Yo-yo loach or Pakistan loach - Should be at least 16" wide
Botia striata - Zebra loach
Glossolepis incisus - Red rainbowfish Should be at least 16" wide
Melanotaenia boesemani - Boeseman's rainbow Should be at least 16" wide
Metynnis hypsauchen - Silver dollar Tall tank Should be at least 18" wide
Puntius denisonii - Red Line Torpedo barb Should be at least 16" wide
Rasbora caudimaculata - Red Scissortail Should be at least 16" wide
Thorichthys meeki - Firemouth Should be at least 18" wide
Trichogaster trichopterus - Blue/Three-spot gourami
Others
Botia kubotai Should be at least 16" wide
Botia histronica Should be at least 16" wide
Botia dario Should be at least 16" wide
Giant danio
Botia rostrata Should be at least 16" wide
72" +
All of the above
Chromobotia macracanthus - Clown loach Also read this Should be at least 36" wide
Hypostomus punctatus - Common pleco Should be at least 30" wide
Balanteocheilus melanopterus - Bala or silver shark Should be at least 36" wide
Just thought it would be useful.
I hope everyone agrees. If not post here or pm me. Also there are ones i have missed, i'm tired at the moment so if you have a couple to add pm me, same if any of the links are in the wrong place.
Cheers
David