{"id":10615,"date":"2023-09-12T10:39:21","date_gmt":"2023-09-12T09:39:21","guid":{"rendered":"https:\/\/neuronicdev.es\/bpa\/education\/do-fish-sleep-at-night\/"},"modified":"2025-08-15T11:27:30","modified_gmt":"2025-08-15T10:27:30","slug":"do-fish-sleep-at-night","status":"publish","type":"post","link":"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/","title":{"rendered":"Do Fish Sleep at Night?"},"content":{"rendered":"

If you\u2019ve ever wondered, \u201cdo fish sleep at night?\u201d, <\/em>you\u2019re not alone.<\/p>\n

It\u2019s amazing how many visitors to Blue Planet Aquarium ask about the sleeping habits of our residents, along with other slumber-related queries like \u201cdo fish close their eyes?\u201d, \u201cdo fish yawn?\u201d, <\/em>and \u201cdo fish hibernate?\u201d.<\/em><\/p>\n

So, to answer such questions once and for all, we thought it was high time we dedicated a whole blog to the sleeping habits of fish. Find out if fish really do sleep, and how, below.<\/p>\n

Do fish sleep?<\/h2>\n

\u201cSort of\u201d may not be the definitive answer you\u2019re looking for, but it\u2019s the only one we can give.<\/p>\n

You see, while fish don\u2019t sleep in the same way as land-dwelling animals \u2013 you know, eyes shut, laid down, all of that \u2013 evidence shows that they do at least rest. And this makes sense given that almost every animal on earth exhibits this behaviour to rejuvenate their bodies and \u201crecharge their batteries\u201d, as it were.<\/p>\n

How do biologists know that fish sleep? Well, plenty of testing has been done in this area, with the sleep patterns of fish monitored by researchers. In laboratory conditions, tests show that \u201csleeping\u201d fish have a slower heart rate and reduced neurological activity, just like mammals, reptiles and birds.<\/p>\n

So, yes, we guess fish do <\/em>sleep, but not in the way you expect.<\/p>\n

\"\"<\/figure>\n

How do fish sleep?<\/h2>\n

Biologists believe that fish \u201csleep\u201d by reducing their overall activity. That means not swimming as far or as fast, or coming to a complete stop in some cases.<\/p>\n

Some fish have even been observed wedging themselves into small crevices or under mud to catch some shut-eye; in particular, blue tangs will sleep in rocks all wedged in together, which are sometimes called dory hotels! Parrotfish create a mucus cocoon or bubble when they sleep, in order to protect themselves from parasites and to mask its own scent from predators.<\/p>\n

Rabbitfish can also change their colours and camouflage at night when they are asleep, ensuring they are safe from passing predators while they rest!<\/p>\n

Many species of fish remain stationary while they rest and will choose a sheltered spot to snooze in peace \u2013 just like us! For some fish, however, including certain sharks, remaining still isn\u2019t an option, as they need to move constantly in order for their gills to work. So, yes, it is possible that fish sleep while swimming.<\/p>\n

When do fish go to sleep?<\/h2>\n

When we think of sleep, we think of animals being either diurnal (asleep at night, awake during the day) or nocturnal (asleep during the day, awake at night). But what about fish?<\/p>\n

Well, it\u2019s much the same story. Some fish are active during the day and less active at night, indicating that they\u2019re diurnal. Others spend their days resting before prowling for prey through the night.<\/p>\n

Either way, scientists agree that fish have regular \u201csleep\u201d patterns, just like us and other animals. They will rest at the same time each day to maintain a regular sleep schedule, which can help to maintain good health and boost their resistance to disease.<\/p>\n

\"\"<\/figure>\n

Do fish close their eyes?<\/h2>\n

After asking the question, \u201cdo fish sleep?\u201d, <\/em>many visitors to Blue Planet follow this up with, \u201cdo they close their eyes?\u201d.<\/em><\/p>\n

To this, our answer is always the same: no, because they have no eyelids!<\/p>\n

That\u2019s right, fish don\u2019t have moveable eyelids like mammals. Instead, they have a permanent, fully transparent eye protector, so their eyes remain open all the time \u2013 even when they\u2019re asleep.<\/p>\n

It might seem strange that fish can\u2019t close their eyes but when you think about it, it does make sense.<\/p>\n

Here on land, animals \u2013 including us humans \u2013 need to blink regularly to lubricate our eyes and stop them from drying out. That\u2019s also part of the reason why most terrestrial beings close their eyes when they sleep.<\/p>\n

For fish, the issue of eye lubrication isn\u2019t a problem since they live in the moistest environment there is! There\u2019s simply no need for them to blink or close their eyes because they don\u2019t have to protect their eyes from dryness.<\/p>\n

3 bonus facts about the sleeping habits of fish<\/h2>\n
    \n
  1. Fish have two stages of sleep. <\/strong>This includes \u201cslow-wave sleep\u201d and \u201cparadoxical sleep\u201d, which is often referred to as deep sleep. Unlike mammals, fish don\u2019t enter the rapid eye movement (REM) stage of sleep.<\/li>\n<\/ol>\n
      \n
    1. Fish flick their fins to stay balanced while they sleep. <\/strong>This unique, instinctive behaviour is one of the key tell-tale signs that a fish is in the land of nod.<\/li>\n<\/ol>\n
        \n
      1. Some fish can sleep with half their brain switched off at a time. <\/strong>For those fish that need to keep swimming even when they are asleep, they can put one half of their brain to sleep to keep the other half active! This is known as unihempispheric sleep.<\/li>\n<\/ol>\n

        So, fish do sleep \u2013 who knew?! We hope this guide has shed light on the fascinating world of fish that few people ever think about. To learn more about the at-times weird and wonderful world of fish, <\/strong>book your tickets to Blue Planet Aquarium<\/strong><\/a> today.<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

        If you\u2019ve ever wondered, \u201cdo fish sleep at night?\u201d, you\u2019re not alone. It\u2019s amazing how many visitors to Blue Planet Aquarium ask about the sleeping habits of our residents, along with other slumber-related queries like \u201cdo fish close their eyes?\u201d, \u201cdo fish yawn?\u201d, and \u201cdo fish hibernate?\u201d. So, to answer such questions once and for … Continued<\/a><\/p>\n","protected":false},"author":2,"featured_media":10617,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[6],"tags":[],"class_list":["post-10615","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-education"],"acf":[],"yoast_head":"\nDo Fish Sleep at Night? - Blue Planet Aquarium<\/title>\n<meta name=\"description\" content=\"If you\u2019ve ever wondered, \u201cdo fish sleep at night?\u201d, you\u2019re not alone. Find out about the sleeping habits of fish in our blog here.\" \/>\n<meta name=\"robots\" content=\"noindex, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Do Fish Sleep at Night? - Blue Planet Aquarium\" \/>\n<meta property=\"og:description\" content=\"If you\u2019ve ever wondered, \u201cdo fish sleep at night?\u201d, you\u2019re not alone. Find out about the sleeping habits of fish in our blog here.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/\" \/>\n<meta property=\"og:site_name\" content=\"Blue Planet Aquarium\" \/>\n<meta property=\"article:published_time\" content=\"2023-09-12T09:39:21+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-08-15T10:27:30+00:00\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n\t<meta name=\"twitter:label2\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"5 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/\",\"url\":\"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/\",\"name\":\"Do Fish Sleep at Night? - Blue Planet Aquarium\",\"isPartOf\":{\"@id\":\"https:\/\/neuronicdev.es\/bpa\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/#primaryimage\"},\"thumbnailUrl\":\"\",\"datePublished\":\"2023-09-12T09:39:21+00:00\",\"dateModified\":\"2025-08-15T10:27:30+00:00\",\"author\":{\"@id\":\"https:\/\/neuronicdev.es\/bpa\/#\/schema\/person\/bd01793fc7bd17d848523b4465bb4154\"},\"description\":\"If you\u2019ve ever wondered, \u201cdo fish sleep at night?\u201d, you\u2019re not alone. Find out about the sleeping habits of fish in our blog here.\",\"breadcrumb\":{\"@id\":\"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/#breadcrumb\"},\"inLanguage\":\"en-GB\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/\"]}]},{\"@type\":\"ImageObject\",\"inLanguage\":\"en-GB\",\"@id\":\"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/#primaryimage\",\"url\":\"\",\"contentUrl\":\"\"},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\/\/neuronicdev.es\/bpa\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Do Fish Sleep at Night?\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\/\/neuronicdev.es\/bpa\/#website\",\"url\":\"https:\/\/neuronicdev.es\/bpa\/\",\"name\":\"Blue Planet Aquarium\",\"description\":\"Discover a world beneath the waves\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\/\/neuronicdev.es\/bpa\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-GB\"},{\"@type\":\"Person\",\"@id\":\"https:\/\/neuronicdev.es\/bpa\/#\/schema\/person\/bd01793fc7bd17d848523b4465bb4154\",\"name\":\"admin\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-GB\",\"@id\":\"https:\/\/neuronicdev.es\/bpa\/#\/schema\/person\/image\/\",\"url\":\"https:\/\/secure.gravatar.com\/avatar\/?s=96&d=blank&r=g\",\"contentUrl\":\"https:\/\/secure.gravatar.com\/avatar\/?s=96&d=blank&r=g\",\"caption\":\"admin\"},\"url\":\"https:\/\/neuronicdev.es\/bpa\/author\/admin\/\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Do Fish Sleep at Night? - Blue Planet Aquarium","description":"If you\u2019ve ever wondered, \u201cdo fish sleep at night?\u201d, you\u2019re not alone. Find out about the sleeping habits of fish in our blog here.","robots":{"index":"noindex","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"og_locale":"en_GB","og_type":"article","og_title":"Do Fish Sleep at Night? - Blue Planet Aquarium","og_description":"If you\u2019ve ever wondered, \u201cdo fish sleep at night?\u201d, you\u2019re not alone. Find out about the sleeping habits of fish in our blog here.","og_url":"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/","og_site_name":"Blue Planet Aquarium","article_published_time":"2023-09-12T09:39:21+00:00","article_modified_time":"2025-08-15T10:27:30+00:00","author":"admin","twitter_card":"summary_large_image","twitter_misc":{"Written by":"admin","Estimated reading time":"5 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/","url":"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/","name":"Do Fish Sleep at Night? - Blue Planet Aquarium","isPartOf":{"@id":"https:\/\/neuronicdev.es\/bpa\/#website"},"primaryImageOfPage":{"@id":"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/#primaryimage"},"image":{"@id":"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/#primaryimage"},"thumbnailUrl":"","datePublished":"2023-09-12T09:39:21+00:00","dateModified":"2025-08-15T10:27:30+00:00","author":{"@id":"https:\/\/neuronicdev.es\/bpa\/#\/schema\/person\/bd01793fc7bd17d848523b4465bb4154"},"description":"If you\u2019ve ever wondered, \u201cdo fish sleep at night?\u201d, you\u2019re not alone. Find out about the sleeping habits of fish in our blog here.","breadcrumb":{"@id":"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/#primaryimage","url":"","contentUrl":""},{"@type":"BreadcrumbList","@id":"https:\/\/neuronicdev.es\/bpa\/blog\/do-fish-sleep-at-night\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/neuronicdev.es\/bpa\/"},{"@type":"ListItem","position":2,"name":"Do Fish Sleep at Night?"}]},{"@type":"WebSite","@id":"https:\/\/neuronicdev.es\/bpa\/#website","url":"https:\/\/neuronicdev.es\/bpa\/","name":"Blue Planet Aquarium","description":"Discover a world beneath the waves","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/neuronicdev.es\/bpa\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-GB"},{"@type":"Person","@id":"https:\/\/neuronicdev.es\/bpa\/#\/schema\/person\/bd01793fc7bd17d848523b4465bb4154","name":"admin","image":{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/neuronicdev.es\/bpa\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/?s=96&d=blank&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/?s=96&d=blank&r=g","caption":"admin"},"url":"https:\/\/neuronicdev.es\/bpa\/author\/admin\/"}]}},"_links":{"self":[{"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/wp\/v2\/posts\/10615","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/wp\/v2\/comments?post=10615"}],"version-history":[{"count":1,"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/wp\/v2\/posts\/10615\/revisions"}],"predecessor-version":[{"id":102531,"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/wp\/v2\/posts\/10615\/revisions\/102531"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/"}],"wp:attachment":[{"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/wp\/v2\/media?parent=10615"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/wp\/v2\/categories?post=10615"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/neuronicdev.es\/bpa\/wp-json\/wp\/v2\/tags?post=10615"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}