Knifefish - UnderWaterGreen

underwatergreen

New to aquariums?

Build a confident freshwater aquarium foundation

Start with the essentials before choosing fish, shrimp, snails or plants.

Read the beginner guide
Your First Tank

Start with the aquarium basics

Set up and cycle your tank

Choose fish with confidence
Build Good Habits

Understand your water

Master simple weekly care

Feed your aquarium well
Need a Quick Fix?

Solve common tank problems

Track your tank cycling

Explore all aquarium guides
Before you buy

Check your tank mates

Pick the fish, shrimp and snails you have in mind and see whether they can live together.
Open the compatibility checker
Freshwater fish

Explore freshwater fish

Browse by group or by what your tank needs, with care, size and tank mates on every profile.

Browse all 1,171 fish
Popular Groups

Tetras73

Bettas96

Livebearers62

Corydoras67

Rasboras28

Barbs50

Gouramis25

Rainbowfish19
More Fish Groups

Catfish460

Plecos368

Cichlids131

Discus44

Loaches56

Danios36

Pufferfish19

Killifish11
Browse by Need

Beginner Fish230

Community Fish373

Nano Fish71

Shrimp-Safe Fish208

Fish Care

Fish Care Guides

Feeding

Compatibility

Water Parameters
Find a fish

Search fish by name

Quick filters

Beginner

Peaceful

Bottom dwellers

Top swimmers

Algae and plant eaters
Freshwater shrimp

Freshwater shrimp profiles

From hardy Neocaridina to specialist Sulawesi species, with the water each one needs.

Browse all 74 shrimp
Shrimp Types

Neocaridina Shrimp30

Caridina Shrimp35

Sulawesi Shrimp8

Fan Shrimp3

Other Freshwater Shrimp9
Plan a Shrimp Tank

Shrimp Tank Plants304

Shrimp-Safe Fish208

Nano Fish71

Mosses13

Compatibility Checker
Shrimp Care

Shrimp Tank Setup

Water Parameters

Breeding

Feeding

Compatibility
Find a shrimp

Search shrimp by name

Quick filters

Beginner

Neocaridina

Caridina

Sulawesi
Snails and invertebrates

Explore freshwater invertebrates

Snails, crabs and crayfish, with what each one eats and whether it will breed in your tank.

Browse all 17 snails
Snails

Nerite Snails2

Mystery Snails2

Rabbit Snails5

Assassin Snails1

Ramshorn Snails1

Trumpet Snails1
Crabs & Crayfish

Freshwater Crabs2

Vampire Crabs2

Crayfish3

Dwarf Crayfish1
Invertebrate Care

Snail Care and Pest Snails

Crab and Crayfish Care

Feeding

Compatibility

Water Parameters

Breeding
Find a snail

Search snails by name

Quick filters

Algae eaters

Beginner

Gives live young

Won't breed in freshwater
Aquarium plants

Find plants for every aquarium

Browse by plant type or by what your tank can give, from low-light epiphytes to high-tech carpets.

Browse all 309 plants
Plant Types

Stem Plants74

Rhizome Plants109

Rosette Plants94

Mosses13

Floating Plants9

Carpeting Plants6
Browse by Need

Beginner Plants164

Low-Light Plants229

No-CO₂ Plants

Shrimp Tank Plants304
Plant Care

Plant Care Guides

Plant Problems

Lighting

CO₂

Fertilizers

Algae Control
Find a plant

Search plants by name

Quick filters

Beginner

Low light

No CO₂ needed

Foreground

Floating
Practical help, right when you need it

Make your next aquarium decision easier

From your first setup to stubborn tank problems, find clear freshwater guidance without the guesswork.

Browse all guides
Start Strong

Build your first aquarium

Set up and cycle it safely

Get water parameters right

Compare methods and equipment
Care With Confidence

Feed fish, shrimp, and snails well

Plan compatible tank mates

Keep up with easy maintenance

Get ready for summer and winter
Go Further

Design a beautiful aquascape

Choose equipment that fits

Understand aquarium equipment

Look after filters and heaters

Troubleshoot a tank problem
Not sure where to begin?

Start with the freshwater essentials

Follow a simple, beginner-friendly path from empty tank to healthy aquarium.
Explore Start Here
Free aquarium tools

Plan your tank before you buy

Check compatibility, find species that suit your tank, and work out the sums for water, heat and flow.

See all tools
Choose Your Fish

Tank Compatibility Checker

Fish Finder

Aquarium Volume Calculator
Equipment & Water

Heater and Filter Calculator

Water Change and Dosing Calculator

Cycling Helper
Learn the Basics

Set up and cycle your tank

Understand your water

Simple weekly care
Not sure what fits?

Start with the Fish Finder

Enter your tank size and water, and see the species that suit it.
Find fish for my tank

Menu

New to aquariums?

Build a confident freshwater aquarium foundation

Start with the essentials before choosing fish, shrimp, snails or plants.

Read the beginner guide
Your First Tank

Start with the aquarium basics

Set up and cycle your tank

Choose fish with confidence
Build Good Habits

Understand your water

Master simple weekly care

Feed your aquarium well
Need a Quick Fix?

Solve common tank problems

Track your tank cycling

Explore all aquarium guides
Before you buy

Check your tank mates

Pick the fish, shrimp and snails you have in mind and see whether they can live together.
Open the compatibility checker
Freshwater fish

Explore freshwater fish

Browse by group or by what your tank needs, with care, size and tank mates on every profile.

Browse all 1,171 fish
Popular Groups

Tetras73

Bettas96

Livebearers62

Corydoras67

Rasboras28

Barbs50

Gouramis25

Rainbowfish19
More Fish Groups

Catfish460

Plecos368

Cichlids131

Discus44

Loaches56

Danios36

Pufferfish19

Killifish11
Browse by Need

Beginner Fish230

Community Fish373

Nano Fish71

Shrimp-Safe Fish208

Fish Care

Fish Care Guides

Feeding

Compatibility

Water Parameters
Find a fish

Search fish by name

Quick filters

Beginner

Peaceful

Bottom dwellers

Top swimmers

Algae and plant eaters
Freshwater shrimp

Freshwater shrimp profiles

From hardy Neocaridina to specialist Sulawesi species, with the water each one needs.

Browse all 74 shrimp
Shrimp Types

Neocaridina Shrimp30

Caridina Shrimp35

Sulawesi Shrimp8

Fan Shrimp3

Other Freshwater Shrimp9
Plan a Shrimp Tank

Shrimp Tank Plants304

Shrimp-Safe Fish208

Nano Fish71

Mosses13

Compatibility Checker
Shrimp Care

Shrimp Tank Setup

Water Parameters

Breeding

Feeding

Compatibility
Find a shrimp

Search shrimp by name

Quick filters

Beginner

Neocaridina

Caridina

Sulawesi
Snails and invertebrates

Explore freshwater invertebrates

Snails, crabs and crayfish, with what each one eats and whether it will breed in your tank.

Browse all 17 snails
Snails

Nerite Snails2

Mystery Snails2

Rabbit Snails5

Assassin Snails1

Ramshorn Snails1

Trumpet Snails1
Crabs & Crayfish

Freshwater Crabs2

Vampire Crabs2

Crayfish3

Dwarf Crayfish1
Invertebrate Care

Snail Care and Pest Snails

Crab and Crayfish Care

Feeding

Compatibility

Water Parameters

Breeding
Find a snail

Search snails by name

Quick filters

Algae eaters

Beginner

Gives live young

Won't breed in freshwater
Aquarium plants

Find plants for every aquarium

Browse by plant type or by what your tank can give, from low-light epiphytes to high-tech carpets.

Browse all 309 plants
Plant Types

Stem Plants74

Rhizome Plants109

Rosette Plants94

Mosses13

Floating Plants9

Carpeting Plants6
Browse by Need

Beginner Plants164

Low-Light Plants229

No-CO₂ Plants

Shrimp Tank Plants304
Plant Care

Plant Care Guides

Plant Problems

Lighting

CO₂

Fertilizers

Algae Control
Find a plant

Search plants by name

Quick filters

Beginner

Low light

No CO₂ needed

Foreground

Floating
Practical help, right when you need it

Make your next aquarium decision easier

From your first setup to stubborn tank problems, find clear freshwater guidance without the guesswork.

Browse all guides
Start Strong

Build your first aquarium

Set up and cycle it safely

Get water parameters right

Compare methods and equipment
Care With Confidence

Feed fish, shrimp, and snails well

Plan compatible tank mates

Keep up with easy maintenance

Get ready for summer and winter
Go Further

Design a beautiful aquascape

Choose equipment that fits

Understand aquarium equipment

Look after filters and heaters

Troubleshoot a tank problem
Not sure where to begin?

Start with the freshwater essentials

Follow a simple, beginner-friendly path from empty tank to healthy aquarium.
Explore Start Here
Free aquarium tools

Plan your tank before you buy

Check compatibility, find species that suit your tank, and work out the sums for water, heat and flow.

See all tools
Choose Your Fish

Tank Compatibility Checker

Fish Finder

Aquarium Volume Calculator
Equipment & Water

Heater and Filter Calculator

Water Change and Dosing Calculator

Cycling Helper
Learn the Basics

Set up and cycle your tank

Understand your water

Simple weekly care
Not sure what fits?

Start with the Fish Finder

Enter your tank size and water, and see the species that suit it.
Find fish for my tank

Find a species

Search Knifefish

Black Ghost Knifefish

Clown Featherback Knifefish

Care guides for Knifefish

Plan it with our tools