Are bugs and fish warmblooded or coldblooded?

Question

if they are coldblooded, how come fish can live in the dark, cold abyss and how come spiders can live in dark places like closets?

Answer 1

Those two words do not adequately describe the thermoregulation of either.  The body temperature of a fish or insect is close to the environmental temperature surrounding the animal.  So it might be cold or it might be hot.  The proper term is ectotherms.  Birds and mammals are endotherms.

http://wc.pima.edu/~bfiero/tucsonecology...

Answer 2

coldblooded, they have no internal regulation of their body temperature so they are coldblooded.

Answer 3

Arthropods and fish are properly described as ectotherms or poikilotherms - their body temperature matches the temperature of their environment.  Some can regulate their body temperature to some extent (e.g., bumblebees vibrating their wings to warm up on cool mornings or incubating species of female pythons contracting their muscles to warm their eggs), but none have the tight control over body temperature exhibited by most mammals.  

Different ectotherms are adapted to different temperature ranges.  Anemones, sea stars, crabs, and other ectotherms in the Antarctic are active at temperatures below the freezing point of pure water, while extreme desert species like horned toads become inactive below ~90 degrees Farenheit.  

Interestingly, there are a few mammals that are essentially ectothermic as well.  Sloths, especially three-toed sloths, can only warm their bodies by a few degrees, and their body temperature ranges from ~28 to ~40 degrees Celsius.  This is very different from most mammals, which become ill if their body temperature varies by more than a couple of degrees.

Answer 4

Neither fish nor bugs internally regulate their body temperature. They are referred to as being "cold-blooded," though their body temperature is not actually necessarily cold.

Many (all?) sorts of reptiles are also cold-blooded, and which is why desert lizards will lay out on a warm rock in the sun to warm up. If they are cold, they become sluggish; when they are warm, they're ready to go out hunting. I also know that people put newts in their fridge while they go on vacation, and the newts' metabolism slows down enough as a result that they do not need to be fed during the time the family's away.

So "cold-blooded" doesn't necessarily have to be cold, nor hot, nor does it have to be within a temperature range that humans would enjoy. Fish and spiders can live in cold places so long as the temperature of their surroundings is within their tolerance range. I don't think many (if any) fish could survive in waters around 130 degrees Farenheit, while many of them could survive anywhere in a range from the low 30s (above freezing) to the 60s. Cold-blooded animals do not need to be warmed by sunlight, necessarily, in order to survive. They just need a comfortable amount of  heat, which they can get from the air/water around them.