The Deep Green Widow Tetra is a genetically modified fluorescent version of the Black Widow Tetra, developed to display a bright glowing green coloration under normal and blue LED lighting. It is part of the popular GloFish ornamental aquarium line.

Overview

• Scientific origin: Based mainly on the Black Widow Tetra

• Type: Genetically modified fluorescent ornamental tetra

• Adult size: 5–6 cm (2–2.5 inches)

• Lifespan: Around 3–5 years

• Temperament: Peaceful schooling fish

The “Deep Green” variety is known for:

• intense fluorescent green coloration

• active schooling behavior

• beginner-friendly care

• compatibility with community aquariums

Appearance

Main characteristics:

• glowing deep green body coloration

• laterally compressed tetra body shape

• translucent fins

• reflective fluorescent effect

Under:

• blue LED lighting

• actinic aquarium lighting

their colors become:

• dramatically brighter

• neon-like in appearance

High-quality specimens usually display:

• even fluorescent coloration

• healthy finnage

• active schooling behavior

• symmetrical body shape

Juveniles are often lighter and intensify with maturity.

What is GloFish?

GloFish are genetically modified aquarium fish developed using fluorescent protein genes originally derived from:

• jellyfish

• sea anemones

• coral species

The modification allows fish to naturally produce:

• fluorescent pigments

The color is:

• permanent

• inherited genetically

• not injected or dyed

Deep Green Widow Tetras are among the most popular fluorescent tetra varieties.

Temperament

Deep Green Widow Tetras are:

• peaceful

• social

• active

• schooling fish

Recommended:

• keep at least 6–10 individuals

Larger schools help:

• reduce stress

• improve behavior

• create stronger schooling displays

Like standard Black Widow Tetras, they can occasionally:

• nip fins if overcrowded or stressed

Aquarium setup

Minimum tank size

• Around 75 liters (20 gallons)

Ideal setup

• planted aquarium

• open swimming space

• moderate filtration

• subdued or blue LED lighting

Popular décor:

• dark substrate

• driftwood

• plants

• glowing aquarium themes

Blue lighting enhances fluorescent coloration dramatically.

Water parameters

Recommended conditions:

• Temperature: 22–28°C

• pH: 6.0–7.5

• Soft to moderately hard water

• Ammonia/Nitrite: 0

• Low nitrate levels

They are relatively hardy and adaptable.

Diet

Deep Green Widow Tetras are omnivores.

Common foods:

• quality flakes

• micro pellets

• frozen bloodworms

• daphnia

• brine shrimp

• small live foods

A varied diet helps maintain:

• activity

• immunity

• overall health

Their fluorescent coloration does not require special color-enhancing foods.

Compatibility

Suitable tankmates:

• rasboras

• peaceful tetras

• corydoras

• danios

• mollies

• peaceful gouramis

Avoid:

• aggressive predators

• large cichlids

• very delicate long-finned fish

They do best in peaceful community tanks.

Breeding

Breeding behavior is similar to standard Black Widow Tetras.

Breeding process:

1. Pair or group spawning

2. Egg scattering among plants

3. No parental care

Breeding setup:

• soft slightly acidic water

• dim lighting

• fine-leaf plants

Eggs usually hatch within:

• 24–36 hours

Fry foods:

• infusoria

• powdered fry food

• baby brine shrimp later

Not all offspring may show identical coloration intensity.

Common health problems

Fin nipping injuries

Possible in:

• overcrowded tanks

• undersized schools

Ich

Symptoms:

• white spots

• scratching behavior

Stress fading

Can occur due to:

• poor water quality

• unstable conditions

Good maintenance keeps them hardy and active.

Care difficulty

Deep Green Widow Tetras are:

• beginner-friendly aquarium fish

Main requirements:

• schooling groups

• stable water quality

• adequate swimming space

• peaceful tankmates

They are generally hardy and adaptable.

Ethical and legal considerations

GloFish are:

• legally sold in some countries

• restricted or banned in others

Their popularity sometimes creates debate regarding:

• genetic modification in ornamental fishkeeping

However:

• they are not harmful to humans

• they behave similarly to regular tetras

Difference from Standard Black Widow Tetra

Compared to Black Widow Tetra:

• Deep Green Widow Tetras display fluorescent green coloration

• Standard Black Widow Tetras have gray-black natural coloration

Behavior and care are largely similar.

Why aquarists value them

Deep Green Widow Tetras are admired for:

• glowing fluorescent appearance

• active schooling behavior

• beginner-friendly care

• dramatic lighting effects

A large school under blue LED lighting creates a vivid and futuristic freshwater aquarium display.