Can Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby) Live Together?

Reviewed by Guidarium Editorial DeskUpdated April 28, 2026
Not Recommended

Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby) are not recommended as tank mates due to incompatible water types. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Dwarf Neon Rainbowfish (Praecox)

Melanotaenia praecox

Violet Goby (Dragon Goby)

Gobioides broussonnetii

🐠Family Group
Dwarf Neon Rainbowfish (Praecox)
Rainbowfish
Violet Goby (Dragon Goby)
Gobies & Gudgeons
Temperament
Dwarf Neon Rainbowfish (Praecox)
Peaceful (2/10)
Violet Goby (Dragon Goby)
Peaceful (2/10)
Temperature
✓ Compatible
Dwarf Neon Rainbowfish (Praecox)
23–28°C
Violet Goby (Dragon Goby)
23–28°C
pH Range
✓ Compatible
Dwarf Neon Rainbowfish (Praecox)
6.5–8
Violet Goby (Dragon Goby)
7.5–8.5
Hardness (dGH)
✓ Compatible
Dwarf Neon Rainbowfish (Praecox)
5–15
Violet Goby (Dragon Goby)
12–25
Water Type
✗ No overlap
Dwarf Neon Rainbowfish (Praecox)
Freshwater Only
Violet Goby (Dragon Goby)
Brackish Required
Flow Preference
✓ Compatible
Dwarf Neon Rainbowfish (Praecox)
Moderate
Violet Goby (Dragon Goby)
Moderate
Min Tank Volume
Combined: 200 L
Dwarf Neon Rainbowfish (Praecox)
75 L
Violet Goby (Dragon Goby)
200 L
Swimming Level
✓ Different zones
Dwarf Neon Rainbowfish (Praecox)
TopMiddle
Violet Goby (Dragon Goby)
Bottom
🏷️Behavior Tags
Dwarf Neon Rainbowfish (Praecox)
Hyperactive / Fast SwimmerJumper (Lid Required)Aggressive Eater (Starves shy fish)
Violet Goby (Dragon Goby)
NocturnalDigger (Disturbs Substrate)Shy / Slow Moving (Easily Stressed)
Stocking calculator

Can your tank handle Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby)?

Compatibility is only part of the answer. Test both fish with your real tank size, current stock, and maintenance needs to see if you have enough space and a safe stocking level before you add them.

Dwarf Neon Rainbowfish (Praecox)
Violet Goby (Dragon Goby)
Test both in my tank

Behaviour & Temperament

Both Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby) are peaceful species with an aggression score of 2/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

In terms of spatial distribution, Dwarf Neon Rainbowfish (Praecox) prefers the Top (Surface) and Middle (Open Water) zones, whereas Violet Goby (Dragon Goby) occupies the Bottom (Substrate) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

Worth noting: Violet Goby (Dragon Goby) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Dwarf Neon Rainbowfish (Praecox) is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 23°C and 28°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 and 8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 12–15 dGH. Regular testing will ensure conditions stay within this range.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together.

Tank Setup

To house Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby) together, plan for an aquarium of at least 200 litres with a minimum length of 120 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.

Specific environmental needs for this combination include: Plants - Densely covered, Sand (Sifters), Shells (Breeding/Hiding), Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

Why This Pairing Usually Fails in Practice

Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby) are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby).

Show 5 more tank sizes

Diet & Feeding

Feeding time deserves special attention with this pairing. Dwarf Neon Rainbowfish (Praecox) is an aggressive eater that may prevent Violet Goby (Dragon Goby) from getting enough food.

Because Dwarf Neon Rainbowfish (Praecox) is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Violet Goby (Dragon Goby) receives an adequate share.

Frequently Asked Questions

Can Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby) live together?

No. This combination is not recommended. Key incompatibilities — such as different water type needs — make cohabitation unsafe.

What size tank do Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby) need?

A minimum of 200 litres (tank length at least 120 cm) is recommended. This provides enough space for both species to establish their own areas and reduces the likelihood of territorial disputes.

What water temperature is best for Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby) together?

Keep the aquarium between 23°C and 28°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Dwarf Neon Rainbowfish (Praecox) or Violet Goby (Dragon Goby) aggressive?

Dwarf Neon Rainbowfish (Praecox) is peaceful (2/10) and Violet Goby (Dragon Goby) is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Dwarf Neon Rainbowfish (Praecox) and Violet Goby (Dragon Goby) need?

Both species overlap in the 7.5–8 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Does Violet Goby (Dragon Goby) being nocturnal affect compatibility?

Violet Goby (Dragon Goby) is most active after lights-out, which naturally reduces daytime encounters with its tank mate. This can actually be beneficial, as both fish get undisturbed time to feed and explore. Just ensure food reaches Violet Goby (Dragon Goby) during evening hours.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
April 28, 2026
Last updated
April 28, 2026
Issues or corrections?
Contact the editorial team

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