Earlier today we tweeted our #FishInThePost question asking ‘the mucus of which fish species has been historically used and boiled by human for medicinal purposes?’. The answer we were looking for was Tench (Tinca tinca), so well done to @DaniRabaiotto for correctly identifying our fish of the week first. Thanks also to @GarethDDaviesEA and @flyfishypete for also guessing Tench too.

Tweet answer

@DaniRabaiotto correctly answered our #FishInThePost this week on Twitter

Humans used to reportedly boil the mucus of Tench and used this for medicinal purposes after seeing its healing effects on other fish (Wildlife Trust, 2019). This has been widely reported whereby numerous fish species have been seen to rub open wounds and sores against Tench in order to benefit from its healing qualities. This has led to Tench being widely recognized as the ‘fish doctor’, as identified by our tweeters who guessed the correct answer this week! The excessive mucus production of Tench is particularly recognised in Germans-speaking regions of Europe, where it as recognised as ‘Schleie’, derived from the proto-German word for slippery (‘slipan’ – Aqualog, 2013).

Tench possess a deep, olive-green body with distinctive red eyes and black fins (Wildlife Trust, 2019). It can be found in lowland lakes and slow-flowing rivers around the UK. Tench are renown for their resistance to pollution and can survive within hypoxic environments and brackish waters (salinity levels of up to 12% – Kottelat and Freyhof, 2007).

Tench pic

Tench (Tinca tinca) – artwork Stephanie Januchowski-Hartley.

Females can spawn between 1-9 times per year (Kottelat and Freyhof, 2007) and lay small eggs in large quantities (300,000 – 600,000 per female; Aqualog, 2013). Females typically lay eggs within vegetation which are then fertilised by (often multiple) males. Tench typically feed on aquatic insects such as midge larvae, and their feeding events are distinctive when they send ‘pin-prick’ bubbles to the surface.

Tench are widely distributed globally and have been recorded within every continent except Antartica (Hetzler, 2017). Tench are ubiquitous across Europe and have even been introduced into some of the limited areas they are considered non-native (e.g. Ireland and Northern Scandavia; Kottelat and Freyhof, 2007). Tench are widely valued by different societies due to their distinct colours and their shoaling behaviours, which makes them a popular species for coarse anglers in particular. As a food source, the flesh of Tench have been valued differently by different European cultures historically. For example, the Romans did not enjoy the taste of Tench and the poet Ausonios noted that the species was only a suitable food source for ‘common people’ (Aqualog, 2013) and the species is rarely consumed by humans today.

We hope that you enjoyed learning about Tench in our #FishInThePost this week. Stay tuned for our blog post next week!


Aqualog (2013) ‘The Tench – facts and fables’ Aqualog Blog. Available online through <https://www.aqualog.de/en/blog-en/the-tench-facts-and-fables/&gt;. [Accessed 07/03/2019].

Hetzlon, P (2017) ‘Tench can live anywhere and will eat anything. And that’s the problem’ North Country Public Radio. Available online through <https://blogs.northcountrypublicradio.org/allin/2017/07/08/tench-can-live-anywhere-and-will-eat-anything-and-thats-the-problem/&gt;. [Accessed 07/03/2019].

Kottelat M and Freyhof J (2007) Handbook of European freshwater fishes. Publications Kottelat, Cornol, Switzerland.

Wildlife Trusts (2019) Tench. Available online through <https://www.wildlifetrusts.org/wildlife-explorer/freshwater-fish/tench>. [Accessed 07/03/2019].

One thought on “#FishInThePost Tench

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s