r/ReefTank • • 5d ago

No judgment questions zone - October 12, 2026

0 Upvotes

Here is the place to post questions about pest ID, coral/fish ID, your cycle, or any other questions that generally wouldn't start up a conversation. If you have an interesting or unique question please create a new thread so everyone can discuss it in length!

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Pest ID guide

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BRS pest guide

BRS beginner resources

BRS 52 weeks of reefing YouTube series


r/ReefTank • • 2h ago

Any of y'all get tats of your creatures?

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15 Upvotes

This is my pistol shrimp Roland, my little gunslinger


r/ReefTank • • 15h ago

[Pic] Nem Cube

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136 Upvotes

r/ReefTank • • 10h ago

[Pic] Berghia nudibranch eating Aiptasia

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19 Upvotes

r/ReefTank • • 2h ago

looking to rehome a struggling sand-sifting star (NL)

3 Upvotes

hi everyone, i’m aware that this sub has a no selling policy, i am not looking to sell. around 6 months ago when i first set up my aquarium, my LFS sold me a small sand-sifting star, to help with debris in the sand. i had a strong copepod population and they told me he would be fine. doing research afterwards of course i saw that sand sifting stars are not recommended for small or new tanks (mine is both those things). but i couldn’t return him, they told me to just see how he does.

he did well for 5 months, looking plump, active, under the sand 90% of the time, able to right himself. i would bury mysis shrimp and algae pellets following LFS advice and just hope he’s eating. but unfortunately in the past 3-4 days i’ve noticed the tips of his legs are white and appear to be degrading. i’m almost 100% sure this is due to him starving. as such i am looking for anyone in the Netherlands, specifically around South Holland (Delft, Rotterdam, Hague, etc) with a large established tank who would be willing to take him (for free of course), cause i really dont want the little guy to die. :(


r/ReefTank • • 16h ago

My Kole Tang

41 Upvotes

Had this fella for about 3 months now and its put on some nice size! Very happy with the temperament and coloration its giving the tank. Only gripe would be it does not care to eat nori at all LOL as you can see though it spends most the day grazing


r/ReefTank • • 16m ago

Nano tank especial

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• Upvotes

20 gallon nano with a 6 gal side tank ... I let this thing go into the trash heap the last few years but now I've been back on top of it and it's crazy that all the corals survived the obsurd hair and bubble algae outbreak, and have grown back this much already .. some of the SPS were the size of a pinky nail under the hair algae


r/ReefTank • • 2h ago

[Pic] Lounging!

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3 Upvotes

r/ReefTank • • 48m ago

[Pic] This hobby tests me

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• Upvotes

Lost 80% of my chalice overnight. I know it's worth it, but damn... Just when my hammers were getting as big as the one I lost to brown jelly, this happens.

Quarantine bucket, peroxide treatment, scrubbed off the jelly. Not easy to frag the encrusted part so I let it be. An old frag from this same colony is growing on a rock in the corner of the tank, healthy and untouched.


r/ReefTank • • 5h ago

Magnesium, nitrates, and ph.

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6 Upvotes

Im aware I shouldn't be chasing numbers rather than maintaining stability. Why is it that I cannot for the life of me get ph, mag, and nitrate to increase. Weeks of dosing magnesium, ph buffer, and heavy feeding. Stopped kalkwasser kh is up to 11 calcium is 440 magnesium 1300 ph is chillen around 7.8. Zero nitrate. Are the macro algae sucking it up? Do I need more fish? Kinda stumped here, thanks everyone.


r/ReefTank • • 14h ago

Captive Bred and aquacultured only tank

25 Upvotes

After a Southeast Asia trip with loads of snorkelling and diving it's really made me think about my previous purchasing decisions for my reef tanks.

I'm still going to keep reefing, and I'll keep everything I currently own, but I'm going strict captive bred fish only and aquaculture corals for as many as possible.

Too many low fish population reefs in poor condition. Not to say this is everywhere and always but it's enough to make me want to change my practices. Any other reefers follow a strict captive bred and aquacultured only?


r/ReefTank • • 1h ago

Bought a bubble coral in bad shape today and this one came with it

• Upvotes

Anyone know what it is?


r/ReefTank • • 1h ago

[Pic] Is this cyano?

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• Upvotes

I’ve treated with chemi-clean on two separate occasions to no avail. An extended seemed to eradicate it but a few days after the lights came back on it was back and spreading rapidly. Any advice?


r/ReefTank • • 5h ago

[Pic] Reef tank setup

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3 Upvotes

Hi everyone,

I am about to pull the trigger and purchase the following equipment. The last time you convinced me that Red Sea tank are not safe, so I swapped it with waterbox. Could you please tell your opinion about all the devices that I need to start the tank? Do you think something is better to be changed?

Thanks again for your help!


r/ReefTank • • 23h ago

One of the most interesting parts of my tank

73 Upvotes

A paguritta hermit crab that lives in an old Christmas tree worm hole. The rock is about 5" across and houses a mix of inverts including a few clams and about 20 different christmas tree worms of different colors and patterns.


r/ReefTank • • 24m ago

Stocking for 150L

• Upvotes

Just set up a 150L cube, what fish are colourful and reef safe that I can put in this tank? Already have 2 clowns and a starry scooter blenny in there


r/ReefTank • • 1d ago

Post recovery of a crashed tank

147 Upvotes

Tank crashed about a month ago thanks to a certain flatworm products which I might have overdosed 🤣 lost most of my sps and few lps. Glad to see the tank is slowly recovery and luckily all the fish survived 😆


r/ReefTank • • 1h ago

Help with possible sps issue

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• Upvotes

I noticed that the polyps on the green slimers base have stopped extending at all and its not encrusting, how ever polyp extension is great and it is growing, is whats happening at the base a result of the base getting not enough light? Or is this stn?

Pic one is today and the last pic is before i noticed the recession


r/ReefTank • • 19h ago

[Pic] My SoCal peeps how you managing during the power outages?

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27 Upvotes

This generator is a lifesaver. Hope everyone is ok. Peace and love. (Don’t mind the GSP lol)


r/ReefTank • • 1h ago

Marcus!

• Upvotes

Marcus aurelius the Hi fin Goby. Survivor of ick, internal parasites and constant aggression from large fish... not to mention forcibly paring a pistol shrimp who killed the past 2 suitors...... marcus lost his top dorsal fin before he could lay claimover the pistol shrimps domain! Ever since the pistol shrimp has always had his back and has broken his claw multiple times setting the bigger fish in their place protecting marcus and all they have built. Having faced multiple rescapes the pistom shrimp decided to select allies.... Allowing marcus to prosper and perch on sand hill as he pleases. It is only marcus that I see proudly display himself especially after I clean the glass 🗿🗿 hes such a trooper. I also have a scaleless goby/monster goby (i believe it is a scaleless goby) and a scissor tail dartfish which share a home with marcus and the pistol shrimp 💀💀💀 its been months and the two gobys hardly ever come out. Marcus being the only one when I bring white lights and a clean front glass. I believe I trained him in the past that white lights mean feeding time. Which hasnt been the case these past few months. I changed my light schedule the other day to include high whites early in the light cycle and its influenced my fish to become more bold! I care more about this goby than the tomini tang and wrasse in my tank lol.


r/ReefTank • • 6h ago

[Pic] Is my feather duster dead will it crash my tank?

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2 Upvotes

My feather duster work has not come out of his tube for 7 days. This is after one of my cleaner shrimp kept fiddling with his feathers. I am leaving my tank for 7 days and I’m worried if he decomposes it will crash my tank. But I don’t want to remove him if he’s still alive in there. How likely is it that he’s alive after 7 days of not coming out?


r/ReefTank • • 18h ago

[Pic] Stanley’s favorite spot in the tank

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20 Upvotes

r/ReefTank • • 2h ago

[Pic] Lounging!

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1 Upvotes

r/ReefTank • • 1d ago

[Pic] Day one install.

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45 Upvotes

Not new to saltwater, but haven't had a saltwater aquarium in over a decade.

Picked up a complete setup with install for 2.2k

Lights are radion xr15 G4 pros


r/ReefTank • • 20h ago

[Pic] Found on marketplace, surely there's been a leak on this? Their post doesn't give indication anything is wrong though. Nor the price tag.

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14 Upvotes