# Fish self-recognition **URL:** \ **Category:** Factual Questions\ **Created:** [March 27, 2003, 3:38pm UTC](https://boards.straightdope.com/t/fish-self-recognition/164535 "2003-03-27T15:38:32Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![fessie](https://avatars.discourse-cdn.com/v4/letter/f/c37758/32.png) [@fessie](https://boards.straightdope.com/u/fessie)\ **Post date:** [March 27, 2003, 3:38pm UTC](https://boards.straightdope.com/t/fish-self-recognition/164535/1 "2003-03-27T15:38:32Z")
When we added some new fish to our aquarium & they proceeded to school with their kind, it occurred to me - how on earth do they recognize their brethren? With those little fishy eyes on the sides of their heads, they can’t possibly know what they, themselves, look like. Given a quick glance it doesn’t appear they have noses, plus I don’t think scent would transmit through water very well (and, unlike dogs, they don’t go through a sniffing process prior to schooling). Any thoughts? ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [March 27, 2003, 3:50pm UTC](https://boards.straightdope.com/t/fish-self-recognition/164535/2 "2003-03-27T15:50:11Z")
What makes you think fish have poor vision? Just because the eye is tiny doesn’t mean it’s inefficient. The oldest fish fossil discovered dates to between 500 and 540 million years ago. That’s a long time to go without eyes that don’t work right. [http://www.admin.cam.ac.uk/news/pr/1999110401.html](http://www.admin.cam.ac.uk/news/pr/1999110401.html) And why else would all the different species of fish, even closely related ones, have such different color patterns in their scales, if not to help differentiate themselves visually from other species? There wouldn’t seem to be much point to that, if the fish couldn’t see each other clearly. ---
**Author:** ![elfje](https://avatars.discourse-cdn.com/v4/letter/e/e19b73/32.png) [@elfje](https://boards.straightdope.com/u/elfje)\ **Post date:** [March 27, 2003, 3:56pm UTC](https://boards.straightdope.com/t/fish-self-recognition/164535/3 "2003-03-27T15:56:29Z")
[http://www.aquariums.state.nc.us/ata/talk.htm](http://www.aquariums.state.nc.us/ata/talk.htm) there you go! ---
**Author:** ![Algernon](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Algernon](https://boards.straightdope.com/u/Algernon)\ **Post date:** [March 27, 2003, 4:02pm UTC](https://boards.straightdope.com/t/fish-self-recognition/164535/4 "2003-03-27T16:02:18Z")
I think the OP is actually asking two questions: a) how does the fish know what species it is? b) how does the fish recognize other fish of he same species? **DDG** pretty much covers (b) by pointing out that fish are colored / patterned /shaped for a reason. Namely, so that fish can recognize others of their own kind. Fish eyes work fine for that purpose. Question (a) is a little different. I’d wager a WAG that a _Hap Ali_ (a species of Cichlid) knows it’s a _Hap Ali_ due to either imprinting or instinct. I’d be interested in what the biologists here think. ---
**Author:** ![fessie](https://avatars.discourse-cdn.com/v4/letter/f/c37758/32.png) [@fessie](https://boards.straightdope.com/u/fessie)\ **Post date:** [March 27, 2003, 4:48pm UTC](https://boards.straightdope.com/t/fish-self-recognition/164535/5 "2003-03-27T16:48:54Z")
Thank you for clarifying, Algernon - DDG, I didn’t ask if they have vision, but wondered how they establish self-knowledge (especially if it’s based on visual cues) given that they can’t turn their heads to have a look at themselves. Self-knowledge seems to be the primary distinction between humans and other species (language, warfare, familial affection, and use of tools having been eliminated from the list). Well, okay, maybe porn & TV would be the others…anyway, back to the fish. ---
**Author:** ![fessie](https://avatars.discourse-cdn.com/v4/letter/f/c37758/32.png) [@fessie](https://boards.straightdope.com/u/fessie)\ **Post date:** [March 27, 2003, 4:54pm UTC](https://boards.straightdope.com/t/fish-self-recognition/164535/6 "2003-03-27T16:54:03Z")
Should have accessed your link first, elfje; I see that my query has been resolved (I had no idea so much was going on in my little fish tank): Besides a “vocabulary” consisting of grunts, croaks, clicks, and snaps, fish also use other means of communication such as chemical odors, or pheromones, and electrical signals. Some species of fish recognize one another by odor and associate these odors with position in the local social hierarchy. Others use pheromones to attract mates or to signal danger. Electrical signals, small charges emitted when a muscle contracts, are also used to convey a message of aggression, courtship, or recognition to other fish. ---
**Author:** ![elfje](https://avatars.discourse-cdn.com/v4/letter/e/e19b73/32.png) [@elfje](https://boards.straightdope.com/u/elfje)\ **Post date:** [March 27, 2003, 5:15pm UTC](https://boards.straightdope.com/t/fish-self-recognition/164535/7 "2003-03-27T17:15:20Z")
yes, quite amazing, isn’t it? to think that an animal that mute to us is actually very “talkative”! ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 27, 2003, 5:17pm UTC](https://boards.straightdope.com/t/fish-self-recognition/164535/8 "2003-03-27T17:17:47Z")
It seems to me perfectly plausible that a fish would like the look of purple-and-green-striped fish without knowing that it, itself, had purple and green stripes. Or orange and a big dorsal fin, or irridescent blue, or whatever. ---
**Author:** ![Algernon](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Algernon](https://boards.straightdope.com/u/Algernon)\ **Post date:** [March 27, 2003, 5:30pm UTC](https://boards.straightdope.com/t/fish-self-recognition/164535/9 "2003-03-27T17:30:16Z")
**Chronos** , but I don’t believe your scenario happens. So, what _prevents_ a fish with purple and green stripes from being attracted to a irridescent blue fish? Again, I offer imprinting or instinct as possible self-awareness mechanisms. (Personally, I vote for instinct. I’m not sure fish even _do_ imprinting like “the Ugly Duckling”.)