Update 16 - INTERESTING GOBY BEHAVIOUR + WEIRD CREATURE - Native Norwegian cold water tank (180l)

Life goes on in the tank, despite the absence of the Dahlia anemones. Tank is a safer place for many of the smaller critters. Observing some behaviour from one of my two-spotted gobies that I've never seen from them before. Also I put in something I thought was a dead "shell" of something, that suddenly started moving.. If any of you know what this mystery creature is, please leave a comment. Other than that, I'm just checking in on some of the creatures in the tank, (crabs, hermits, clingfish etc.)

Hope you'll enjoy the update.

Tanks for watching!

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Creatures in this video:
Edible sea urchin (Echinus esculentus)
Yarrell's blenny (Chirolophis ascanii)
Two-spotted clingfish (Diplecogaster bimaculata)
Sea orange sponge (Suberites ficus)
Norwegian topknot (Phrynorhombus norvegicus)
Two-spotted goby (Gobiusculus flavescens)
Scorpion spider crab (Inachus dorsettensis)
Stalked jellyfish (Lucernaria quadricornis)
Rock Gunnel (Pholis gunnellus)
Dahlia anemone (Urticina felina)
Brittle star (Ophiurida)

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My setup:
Standard Juwel 180l (48 gallon) glass tank.
Tunze comline reefpack 250 (internal skimmer + filter)
Teco TK 500 aquarium chiller
Sicce Syncra Silent, 2.0 pump
Jebao wavemaker sw8

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Norske navn på arter:
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