Can Assassin Snail and Red Terror (Festa's Cichlid) Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 4, 2026
Not Recommended

Assassin Snail and Red Terror (Festa's Cichlid) are not recommended as tank mates due to piscivorous fish will prey on nano-sized tank mates.. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Assassin Snail

Anentome helena

Red Terror (Festa's Cichlid)

Mesoheros festae

🐠Family Group
Assassin Snail
Invertebrates
Red Terror (Festa's Cichlid)
Cichlids - South American
Temperament
Assassin Snail
Peaceful (2/10)
Red Terror (Festa's Cichlid)
Highly Aggressive (10/10)
Temperature
✓ Compatible
Assassin Snail
22–28°C
Red Terror (Festa's Cichlid)
25–29°C
pH Range
✓ Compatible
Assassin Snail
7–8
Red Terror (Festa's Cichlid)
6.5–8
Hardness (dGH)
✓ Compatible
Assassin Snail
8–15
Red Terror (Festa's Cichlid)
4–18
Water Type
✓ Compatible
Assassin Snail
Freshwater Only
Red Terror (Festa's Cichlid)
Freshwater Only
Flow Preference
✓ Compatible
Assassin Snail
Low
Red Terror (Festa's Cichlid)
Moderate
Min Tank Volume
Combined: 450 L
Assassin Snail
10 L
Red Terror (Festa's Cichlid)
450 L
Swimming Level
Shared: 1 zone
Assassin Snail
Bottom
Red Terror (Festa's Cichlid)
MiddleBottom
🏷️Behavior Tags
Assassin Snail
Nano / Bite-sized (Predation Risk)Snail EaterDigger (Disturbs Substrate)
Red Terror (Festa's Cichlid)
Piscivore (Eats small/nano fish)Generally AggressiveTerritorial (Defends specific area)Digger (Disturbs Substrate)Plant DestroyerAggressive to same species/look-alikes
Stocking calculator

Can your tank handle Assassin Snail and Red Terror (Festa's Cichlid)?

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.

Assassin Snail
Red Terror (Festa's Cichlid)
Test both in my tank

Behaviour & Temperament

Assassin Snail is a peaceful species (2/10), while Red Terror (Festa's Cichlid) is highly aggressive (10/10). This notable difference means Red Terror (Festa's Cichlid) may occasionally assert dominance over Assassin Snail.

Large aggression gap (8 points) between Assassin Snail and Red Terror (Festa's Cichlid) increases stress risk for the more peaceful fish.

Assassin Snail and Red Terror (Festa's Cichlid) both frequent the Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

There is a critical concern: the Nano / Bite-sized (Predation Risk) behaviour of one fish directly conflicts with the Piscivore (Eats small/nano fish) trait of the other — piscivorous fish will prey on nano-sized tank mates..

Water Parameters

The safe temperature window for both species falls between 25°C and 28°C. Aim for the midpoint of this range (around 26.5°C) for optimal comfort.

Both fish can tolerate a pH between 7 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 8–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Assassin Snail and Red Terror (Festa's Cichlid) together, plan for an aquarium of at least 450 litres with a minimum length of 150 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: Sand (Sifters), Driftwood (Digestion/Hiding), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

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

Why This Pairing Usually Fails in Practice

Assassin Snail and Red Terror (Festa's Cichlid) 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 Assassin Snail and Red Terror (Festa's Cichlid).

Frequently Asked Questions

Can Assassin Snail and Red Terror (Festa's Cichlid) live together?

No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.

What size tank do Assassin Snail and Red Terror (Festa's Cichlid) need?

A minimum of 450 litres (tank length at least 150 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 Assassin Snail and Red Terror (Festa's Cichlid) together?

Keep the aquarium between 25°C and 28°C. A target of around 26.5°C sits comfortably within both species' preferred ranges.

Are Assassin Snail or Red Terror (Festa's Cichlid) aggressive?

Assassin Snail is peaceful (2/10) and Red Terror (Festa's Cichlid) is highly aggressive (10/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Assassin Snail and Red Terror (Festa's Cichlid) need?

Both species overlap in the 7–8 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

How do I manage Red Terror (Festa's Cichlid)'s territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Red Terror (Festa's Cichlid) space to claim a territory without encroaching on the other fish's area. Adding décor that divides the tank into distinct zones works especially well.

Editorial Review

Guidarium Editorial Desk

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

Last reviewed
May 4, 2026
Last updated
May 4, 2026
Issues or corrections?
Contact the editorial team

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