organism
Angelfish vs discus
Two tall South American cichlids often considered as a centrepiece. Which is realistic?
Short answer
The angelfish, unless you are prepared to run a tank at 29 °C with very low nitrate and large frequent water changes. Discus are genuinely demanding rather than merely expensive.
Side by side
| Dimension | Angelfish | Discus | Favours |
|---|---|---|---|
| Adult size | 12–15 cm body | 15–20 cm | — |
| Temperature | 24–29 °C | 28–31 °C | Angelfish |
| Water chemistry | Tolerant | Soft, acidic, very low nitrate | Angelfish |
| Minimum tank | 200 L | 350 L | Angelfish |
| Minimum group | Pair, or six juveniles to pair off | Five or more | Angelfish |
| Water change demand | Normal | Large and frequent | Angelfish |
| Compatible tankmates | Many, above mouth size | Few — the temperature rules most out | Angelfish |
| Eats neon tetras | Yes, once grown | Possible | Neither |
Which to choose
Angelfish
Choose angelfish for a tall community tank, planning for adult size and for what happens when a pair forms.
Discus
Choose discus only with a dedicated setup, a maintenance routine to match, and tankmates chosen for the temperature.
One caveat
Both are cichlids and both will eat small tetras as adults. Neither is a peaceful community fish in the sense the shop tank suggests.