Cause of sand mounds

[Edwardfish]

I’m not sure if my question should go in ID or not but does anyone know the cause of these sand mounds? No sand dwellers or sifters only a bicolor blenny, pods, astrea snails, 2 hermit crabs, and corals. Not sure if it is something alive or not but these mounds are growing in number and in size. Also if it’s something alive is it beneficial? There are more of the mounds not pictured but this is one of the only ones on the glass

[billygoat]

11 minutes ago, Edwardfish said:

I’m not sure if my question should go in ID or not but does anyone know the cause of these sand mounds? No sand dwellers or sifters only a bicolor blenny, pods, astrea snails, 2 hermit crabs, and corals. Not sure if it is something alive or not but these mounds are growing in number and in size. Also if it’s something alive is it beneficial? There are more of the mounds not pictured but this is one of the only ones on the glass

 

Definitely something alive, yeah - but almost certainly nothing to worry about! 😁

 

My guess is that these mounds are made by small burrowing worms that live in your sandbed. Not sure about the exact ID, but they look a lot like the mounds produced by lugworms in colder climes. Lugworms and similar burrowing worms feed by ingesting sand, digesting all the organic matter, bacteria, and other goodies attached to it, and excreting the leftovers on the surface when they are done. This forms small mounds of "waste" sand much like the ones you see in your tank. So that may be what's going on?

 

Worms like these are common in many mature aquariums and are generally considered beneficial, since their activities serve to clean the sandbed and keep it oxygenated. If the mounds bother you, slightly increasing water flow across the sand surface would likely flatten them out (probably without any impact on the activity of the worms).

[Edwardfish]

7 minutes ago, billygoat said:

 

Definitely something alive, yeah - but almost certainly nothing to worry about! 😁

 

My guess is that these mounds are made by small burrowing worms that live in your sandbed. Not sure about the exact ID, but they look a lot like the mounds produced by lugworms in colder climes. Lugworms and similar burrowing worms feed by ingesting sand, digesting all the organic matter, bacteria, and other goodies attached to it, and excreting the leftovers on the surface when they are done. This forms small mounds of "waste" sand much like the ones you see in your tank. So that may be what's going on?

 

Worms like these are common in many mature aquariums and are generally considered beneficial, since their activities serve to clean the sandbed and keep it oxygenated. If the mounds bother you, slightly increasing water flow across the sand surface would likely flatten them out (probably without any impact on the activity of the worms).

Thanks! Glad to know they are probably beneficial and “mature” these and my growing sponges boost my confidence in my new tanks stability. Also glad I now have something to mix up my sand bed. Do you think nassarius snails will mess with these guys if I add some?

[Murphs_Reef]

Yep you can clearly see the tracks under the sand line .. lugworms would be my guess as well

[billygoat]

2 hours ago, Edwardfish said:

Thanks! Glad to know they are probably beneficial and “mature” these and my growing sponges boost my confidence in my new tanks stability. Also glad I now have something to mix up my sand bed. Do you think nassarius snails will mess with these guys if I add some?

Nassarius snails are purely scavengers and have no interest in these worms (or in anything else that isn't dead, for that matter). Their burrowing activity is quite minimal - they only hide themselves under the sand in a single location, and don't really do any actual digging.