Choosing aquarium fish gets a lot easier when you can compare them side by side instead of jumping between random care guides and half-remembered store advice. This Aquarium Fish Species Directory is built as a simple starting point for fishkeepers who want to understand each fish before bringing it home.

Here, you’ll find freshwater and saltwater aquarium fish organised with quick details like minimum tank size, diet, temperament, compatibility, care difficulty, and full care guide links wherever available. Some fish are peaceful community favorites.

Some need bigger tanks, stronger filtration, or more experienced hands. And a few are beautiful troublemakers that beginners should approach carefully.

I’ll keep adding more species to this directory over time, so it can grow into a practical reference for choosing the right fish, planning better tank combinations, and avoiding those “I wish I knew this earlier” aquarium mistakes.

Beginner Fish

Community Fish

Species / Type	Minimum Tank Size	Diet	Temperament	Best Tank Mates	Difficulty	Full Care Guide
Betta Fish	5 gallons minimum; 10+ gallons better for community attempts	Carnivorous; betta pellets, frozen/live foods like bloodworms, brine shrimp, and daphnia	Territorial, especially males; community success depends heavily on personality	Snails, peaceful bottom dwellers, and calm tank mates in larger planted tanks	Beginner-friendly alone; intermediate in community tanks	Betta Fish Care Guide
Dalmatian Molly Fish	20 gallons minimum	Omnivorous; flakes, pellets, algae-based foods, blanched vegetables, occasional protein foods	Peaceful to active; social livebearer that prefers groups	Platies, swordtails, other mollies, peaceful community fish, some bottom dwellers	Beginner-friendly if water is stable and tank is spacious	Dalmatian Molly Fish Guide
Danios	10 gallons minimum for smaller species; 20 gallons better for active groups	Omnivorous; flakes, micro pellets, frozen/live foods like daphnia and brine shrimp	Very active, hardy, fast-swimming schooling fish	Rasboras, livebearers, corydoras, peaceful barbs, other active community fish	Very beginner-friendly	Danios Care Guide
Least Killifish	5 gallons minimum; 10 gallons better for a group	Omnivorous micro-predator; crushed flakes, micro pellets, baby brine shrimp, daphnia	Tiny, peaceful, shy, best in calm planted community tanks	Snails, shrimp with caution, tiny rasboras, other peaceful nano fish	Beginner to intermediate due to small size	Least Killifish Care Guide
Clown Killifish	5 gallons minimum; 10 gallons better for a group	Carnivorous micro-predator; tiny floating foods, micro pellets, daphnia, baby brine shrimp	Peaceful, surface-dwelling, shy; prefers low-flow planted tanks	Small rasboras, tiny peaceful nano fish, snails, shrimp with caution	Beginner to intermediate	Clown Killifish Care Guide
Farlowella Catfish	30 gallons minimum	Herbivorous/omnivorous grazer; algae, biofilm, vegetables, sinking wafers	Peaceful, shy, delicate, slow-moving bottom/wood grazer	Peaceful community fish, small tetras, rasboras, corydoras, calm tank mates	Intermediate due to feeding and water-quality needs	Farlowella Catfish Care
Black Lace Angelfish	30 gallons minimum for a pair; taller tanks preferred	Omnivorous; flakes, pellets, frozen/live foods like brine shrimp and bloodworms	Semi-peaceful to semi-aggressive; may become territorial when mature	Larger peaceful community fish, calm tetras, corydoras, some gouramis with caution	Intermediate	Black Lace Angelfish Guide

Aggressive / Semi-Aggressive Fish

Species / Type	Minimum Tank Size	Diet	Temperament	Best Tank Mates	Difficulty	Full Care Guide
Firemouth Cichlid	30 gallons minimum	Omnivorous; quality pellets, flakes, frozen/live foods like bloodworms and brine shrimp	Semi-aggressive; territorial, especially during breeding	Similar-sized peaceful to semi-aggressive cichlids, larger tetras, sturdy community fish	Intermediate	Firemouth Cichlid Guide
Electric Yellow Cichlid	40 gallons minimum; larger for groups	Omnivorous with herbivorous lean; cichlid pellets, spirulina, algae-based foods, occasional protein	Semi-aggressive African cichlid; active and territorial	Other compatible Lake Malawi cichlids with similar size and temperament	Intermediate	Electric Yellow Cichlid Guide
Peacock Cichlid	55 gallons minimum	Carnivorous/omnivorous; cichlid pellets, frozen foods, krill, brine shrimp, occasional live foods	Semi-aggressive; generally calmer than many Mbuna but still territorial	Other peaceful to semi-aggressive African cichlids, carefully chosen Peacock/Hap species	Intermediate	Peacock Cichlid Care
Albino Oscar Fish	75 gallons minimum for one adult	Carnivorous/omnivorous; large cichlid pellets, insects, shrimp, worms, occasional frozen foods	Large, bold, predatory, intelligent; will eat smaller tank mates	Large sturdy fish only, such as some large catfish or similar-sized cichlids with caution	Intermediate to advanced	Albino Oscar Fish Care Guide
Black Lace Angelfish	30 gallons minimum for a pair; taller tanks preferred	Omnivorous; flakes, pellets, frozen/live foods like bloodworms and brine shrimp	Semi-peaceful to semi-aggressive; may become territorial when mature or breeding	Larger peaceful community fish, calm tetras, corydoras, and non-nippy tank mates	Intermediate	Black Lace Angelfish Guide
Dwarf Pea Puffer	5 gallons minimum for one; 10+ gallons better for more planning	Carnivorous; live/frozen foods like bloodworms, daphnia, brine shrimp, and small snails	Tiny but territorial, curious, and often nippy; not a typical community fish	Best in species-only setups; tank mates are risky and must be chosen carefully	Intermediate	Dwarf Pea Puffer Care
Iridescent Shark	300+ gallons long-term; unsuitable for most home aquariums	Omnivorous; sinking pellets, protein foods, vegetables, occasional frozen foods	Large, fast, skittish, powerful schooling catfish; not aggressive in the usual way but risky due to size	Only very large, peaceful, similarly sized fish in massive aquariums	Advanced	Iridescent Shark Care

Bottom Feeders

Species / Type	Minimum Tank Size	Diet	Temperament	Best Tank Mates	Difficulty	Full Care Guide
Farlowella Catfish	30 gallons minimum	Herbivorous/omnivorous grazer; algae, biofilm, blanched vegetables, sinking wafers, and occasional supplemental foods	Peaceful, shy, slow-moving, and delicate; prefers calm, mature planted tanks	Peaceful community fish, small tetras, rasboras, corydoras, and other non-aggressive tank mates	Intermediate due to feeding needs and sensitivity to poor water quality	Farlowella Catfish Care
Iridescent Shark	300+ gallons long-term; unsuitable for most home aquariums	Omnivorous; sinking pellets, protein foods, vegetables, and occasional frozen foods	Large, fast-growing, skittish schooling catfish; not a true “cleaner fish” despite being a bottom/mid-level catfish	Only very large, peaceful, similarly sized fish in massive aquariums	Advanced	Iridescent Shark Guide

Saltwater Fish

Species / Type	Minimum Tank Size	Diet	Temperament	Best Tank Mates	Difficulty	Full Care Guide
Tangs/Surgeonfish	75 gallons minimum for smaller tangs; 100+ gallons better for most	Mostly herbivorous; marine algae, nori, spirulina foods, quality marine pellets	Active, bold, territorial toward similar-shaped tangs	Clownfish, wrasses, gobies, blennies, peaceful to semi-aggressive marine fish	Intermediate to advanced	Tang Saltwater Fish Guide

Happy Fishkeeping!