HomeCompare fishHead-and-taillight tetra vs Northern trout gudgeon Head-and-taillight tetra vs Northern trout gudgeon: can they live together? Verdict: Not recommendedThe Northern trout gudgeon can be semi-aggressive or nip fins.An adult Northern trout gudgeon is about 4 times the length of a Head-and-taillight tetra and may eat it.Both are comfortable at 24–26°C (75–79°F).A pH of 6.0–7.8 suits both.Side by sideHead-and-taillight tetraNorthern trout gudgeonAdult size5 cm (2 in)17.5 cm (6.9 in)Minimum tank75 L (20 US gal)150 L (40 US gal)Temperature22–26°C (72–79°F)24–26°C (75–79°F)pH6.0–8.06.0–7.8Hardness5–19 dGH (89–339 ppm)–TemperamentPeacefulSemi-aggressiveCommunity tankExcellentGoodCare levelEasyEasyDietOmnivoreOmnivoreSpecies profilesHead-and-taillight tetraHemigrammus ocelliferNorthern trout gudgeonMogurnda mogurnda