Stars with 6 legs in seawater aquarium

Click For Summary

Discussion Overview

The discussion revolves around the identification of a marine organism observed in a seawater aquarium, specifically a small white star-like creature with six legs, which raises questions about its classification and characteristics compared to typical starfish.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant notes the observation of a small white star with six legs, questioning its identity since starfish typically have five legs.
  • Another participant suggests searching for "hexaradial starfish" and provides a link to a website that may contain relevant information, though they express uncertainty about the site's credibility.
  • A third participant mentions that while sea stars usually have five arms, some species can have many more, citing the sunflower star as an example with up to 40 arms.
  • A repeated suggestion to explore the same website for information on echinoderms is made, with one participant asserting that the site seems reliable based on their knowledge of the subject.
  • A later reply indicates that the observed stars resembled Asterina species, which are discussed in various aquaristic forums, providing a link for further reference.

Areas of Agreement / Disagreement

Participants express varying levels of certainty about the identification of the organism, with some proposing potential matches while others highlight the variability in starfish morphology. No consensus is reached regarding the exact identity of the six-legged stars.

Contextual Notes

The discussion reflects a lack of definitive identification and relies on external sources for information, which may vary in credibility. Assumptions about the characteristics of starfish and the specific species observed remain unverified.

DrDu
Science Advisor
Messages
6,423
Reaction score
1,004
Recently I visited a sea water aquarium with tropical fish anemona, corals. At the glas walls I observed little (about 1 cm diameter) white stars with 6 legs.
Now starfish have 5 legs, as far as I know.
Any idea what this could have been?
 
Biology news on Phys.org
Sea stars mostly have 5 "arms" or "legs". Some have more - up to 40 arms.
The sun star can have 40:

http://0.tqn.com/d/marinelife/1/0/C/5/-/-/Sunflowerstar-500x3750-Patrickbriggsflickr.jpg
 
Borek said:
Googling for hexaradial starfish finds this page:

http://www.wetwebmedia.com/ca/volume_1/cav1i4/echinoderms/echinoderms.htm

Scroll down to the green table. No idea about the site credibility, but at least it gives some ideas about what to look for.

The site seems pretty reliable and as far as I know (about echinoderms), the information provided is correct.
 
Thank you all very much for the info. I didn't know that there is so much variability in the number of arms in starfish. The ones I saw resembled very much Asterina species which are described in several aquaristic forums, like here:
http://reefkeepingfever.com/forum/forum_posts.asp?TID=12
 
Last edited by a moderator:

Similar threads

Hiking, traveling in remote locations, especially in hot summer months
  • · Replies 25 ·
Replies
25
Views
2K
Lawn/Garden Cycling water, nutrients in pots, garden beds, containers, hydroponics
  • · Replies 2 ·
Replies
2
Views
3K
Low-energy air conditioning with seawater
  • · Replies 2 ·
Replies
2
Views
2K
Undergrad Calculating the Hodge Star in the most general case
  • · Replies 29 ·
Replies
29
Views
4K
Structure of the Galaxy: 6 Questions Confirmed
  • · Replies 31 ·
2
Replies
31
Views
4K
Lense with two mediums speed of a fish in an aquarium
  • · Replies 1 ·
Replies
1
Views
7K
Writing: Input Wanted What are the Consequences of a Longer PETM?
  • · Replies 10 ·
Replies
10
Views
2K
How Does Refraction Affect the Visibility of a Fish Inside a Spherical Bowl?
  • · Replies 23 ·
Replies
23
Views
11K
Undergrad Challenges to the Redshift Method and Hubble's Law
  • · Replies 5 ·
Replies
5
Views
3K
Storing chemicals on my balcony (storing in changing temps)
  • · Replies 14 ·
Replies
14
Views
3K