Could I keep them together by running the tank at 72F?

72F sits at the top of the goldfish range and the bottom of the rummy nose range. Goldfish will be overheated and stressed. Rummy nose tetras will barely tolerate it but lose their coloration and stop schooling properly.

Goldfish are opportunistic feeders. Will they eat rummy nose tetras?

Yes. Full-sized goldfish at 6-12 inches are large enough to swallow 2-2.5 inch rummy nose tetras. Even if the temperature were workable, goldfish would hunt the tetras as prey.

What tropical fish can live with goldfish?

None that thrive long-term. Goldfish need coldwater conditions below 72F. No tropical fish tolerates these temperatures well. Keep goldfish with coldwater companions or move them to a tropical setup with appropriate tankmates.

Can Goldfish Live With Rummy Nose Tetra?

By Alex WalshLast reviewed Apr 18, 2026

No, goldfish and rummy nose tetras share no temperature overlap, with goldfish needing cool water (60-72F) and rummy nose tetras requiring warm water (75-84F).

Why

Goldfish are coldwater fish thriving at 60-72F, with 65F being ideal.
Rummy nose tetras are tropical fish needing 75-84F, with 80F being ideal.
The temperature overlap between these ranges is zero. There is no shared temperature that works for both.
Goldfish held above 75F develop heat stress, metabolic acceleration, and a dramatically shortened lifespan.
Rummy nose tetras held below 73F become sluggish, lose their red nose coloration, and die from temperature shock.

Minimum shared tank

30 gallons

What could go wrong

Goldfish overheat and age prematurely at rummy nose temperatures, while rummy nose tetras chill and die at goldfish temperatures, with no middle ground possible.

If you keep them in separate tanks

Sized for the 30 gallon minimum this pairing needs. Affiliate links — we earn a small commission if you buy through them.

AquaClear 70 Power Filter

Oversized filtration is what lets you stock two species together without water quality crashing. Rated for a tank slightly larger than the 30 gallon minimum.

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API Freshwater Master Test Kit

Keep ammonia, nitrite, and nitrate in check. Two-species tanks have more bioload and less margin for error than single-species setups.

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Better pairings to consider

Goldfish do well with dojo loaches, weather loaches, or other coldwater species in unheated setups. Rummy nose tetras thrive in soft-water tropical communities with cardinal tetras, neon tetras, or harlequin rasboras at 80F.