Red rainbowfish vs Slim betta: can they live together?

Verdict: With caution

The Slim betta can be semi-aggressive or nip fins.
Both are comfortable at 24–25°C (75–77°F).
A pH of 7.0–7.5 suits both.
Minimum tank for the pair: 150 L (40 US gal)

Side by side

	Red rainbowfish	Slim betta
Adult size	12 cm (4.7 in)	10 cm (3.9 in)
Minimum tank	150 L (40 US gal)	75 L (20 US gal)
Temperature	22–25°C (72–77°F)	24–30°C (75–86°F)
pH	7.0–8.0	6.5–7.5
Hardness	9–19 dGH (161–339 ppm)	5–15 dGH (89–268 ppm)
Temperament	Peaceful	Semi-aggressive
Community tank	Good	Good
Care level	Easy	Easy
Diet	Omnivore	Omnivore