Who Gives A Fish Forums

Two questions for you lot - got any advice on how to tackle this issue, and do you think my observations are on the money or way off?

So here's the story - 15 months ago, I moved my SPS from the holding tank into the new 1000L DT after the house move. I got a tiny encrusting Monti frag from a mate, who's a good reefer with solid QT and dip procedures, but I still gave it a good dip in RX and scrubbed it with a toothbrush - I've had nudis before, I'm not daft.

A few weeks later, I noticed these black bugs on the Montipora - all of them, not just the new frag. Did some research, but ultimately left it alone as no damage was done, and after a month or so, they vanished. I never thought much of it, and to be honest, I doubt the frag brought anything in. The tank was new, set up with reefbones, and was covered in diatomous bacteria - growth and colour were great, and I didn't see any black bugs for 6-8 months.

Fast forward to this March, I tried Nualgi - liked the idea of diatoms producing food for the pods. Stopped after 6 weeks as I saw some Montipora decline, initially thinking it was too much filtration. But then I noticed the black bugs again, this time on every Montipora. My Forest Fire Digi was the first to show serious ill health - I had taken some frags a couple of months earlier, which were in my frag area, and they were riddled with the black bugs.

Since then, I've increased nutrients a bit, and most Montipora are in slightly better condition than 2 months ago, but there are still issues - tissue loss, lack of growth, etc. My frag rack is cleaner, but the frags aren't great. I removed and blasted some frags with rank water - a Purple Digi, Red Plate, and Forest Fire Digi - and a lot of black bugs came off, maybe 100.

What I noticed was that they don't move or do anything, but every now and then, they make a burst for it and swim really well - then they just sit motionless. I've never seen this in the tank, but it was easy to spot in a white tub. High pollen counts might be feeding diatomous bacteria, which in turn feeds the black bugs - are they not predators of Montipora at all, just residents that irritate them?

I've got a lot of Montipora, some big ones, and I don't want to lose them. Here's how they're affected:

- Red Plate: infested, no ill effect
- Green Plate: infested, slight colour loss, small patches of die-off
- Pink Peach Plate (A): heavily infested, poorly
- Pink Peach Plate (B): opposite end of the tank, infested, no ill effect
- Red Digi: slight infestation, slight effects
- Green Digi: infested, slight colour loss
- Forest Fire Digi: heavily infested, poorly, but recovering
- Blue Digi: can't see, no ill effect
- Purple Digi: infested, colour loss, small recession
- Purple Plate: slight infestation, no ill effects
- Monti Confusa: slight infestation, no ill effects

Generally, things look improved over the past month, but it's slow progress. Black bug numbers seem to be dwindling, but slowly. My worry is that the Montiporas might not survive if I ride it out, and if they do make it to next spring, I might be back to square one.

Interceptor is an option, but it's hard to get in the UK, and I've got reservations about nuking the pod population. Or do I just rip out the Monti as and when they die and replace with Acro? I don't see the point in dipping as some colonies are huge and can't be dismounted. I've got 3 Halicoeris wrasse and a Jewel, but they're not interested in the bugs, despite them being clearly on view.

Not a peep. I know the post is a beast, but I had to lay out the whole story to get my point across. I'm hoping someone who's dealt with this before might see some similarities and think these little blighters aren't actually predators. If they were, I'd have lost all my monti by now - their numbers are that high.

I'm bracing myself for losses in the next couple of weeks. Some of my monti will be so far gone, it won't be worth keeping what's left. Gutted, to be honest. Three years of growing and nursing them back from disaster, and it's all being undone by this rare pest. I genuinely believe it would slip through even the most rigorous dip and QT process unless the reefer had prior experience with it.

One little bump, hoping someone might've come across something similar and can offer some insight.

I caught sight of the black bugs in my tank last night, along with red bugs on my Acropora, and I decided to take action. I dosed Sentinel today, and I'm pleased to report that both the black bugs and red bugs vanished within 5 hours. I did notice a decline in my pod population, but given that I have a bare bottom tank, I wasn't too concerned about the biological impact.

From what I've gathered, many people have used Sentinel or Intercept without any major issues, and if I were in your shoes, I'd definitely consider using it. It might be worth exploring this option, especially if it could help you resolve the problem quickly.

A mate of mine locally had a similar issue with black bugs, almost from the tank's inception, nearly three years ago. His solution, inadvertently, was having a silver belly and 6 line wrasse that kept the black bug population in check.

He experienced some minor tissue recession on his montiporas every now and then, but they'd grow back without issue. He had some large monti plates and didn't seem too fussed about the black bugs, though the 6 line wrasse was a different story altogether - it wreaked havoc on his tank.

That you Mo from your avatar, didn't bother searching, not much to find anyway. Thanks for the input, both of you.

I've got a trio of Halicoeris wrasse - Melanurus, Richmondi, and a Yellow Canary - plus a Jewel, but none of them show any interest in the black bugs. To be honest, I had a bit of a wrasse drama initially, overdid it, and lost a few to bickering. I thought they might've taken care of the black bugs last year, but now I'm not so sure.

Sentinel/Interceptor might be an option, but it's a hassle to get hold of, and I'm not keen on reducing the wrasse's natural food source. I'm wary of using it, and also of introducing a Sixline, as I think it could be a risk.

I was thinking about dragonets - would a single male Pink Scooter and a harem of females work in a 1000 litre tank, or am I just clutching at straws?

Yeah, that's me. No harm in trying a single dragonet, right? My mate never actually saw them munching on the black bugs that often, but he was convinced it was the wrasses keeping them in check. His SPS tank was incredible, and he never did get rid of the black bugs.

silktwist wrote: ↑Mon Jan 27, 2025 2:09 am A mate of mine locally had a similar issue with black bugs, almost from the tank's inception, nearly three years ago. His solution, inadvertently, was having a silver belly and 6 line wrasse that kept the black bug population in check.

He experienced some minor tissue recession on his montiporas every now and then, but they'd grow back without issue. He had some large monti plates and didn't seem too fussed about the black bugs, though the 6 line wrasse was a different story altogether - it wreaked havoc on his tank.

Would I know your mate, be able to have a chat with him about his experience? I've got a few questions I'd love to ask.

Ultimately, I'm not convinced the wrasses are that interested, there are plenty of black bugs in plain sight on the undersides of the plates and they just swim past without giving them a second glance.

Removing the rocks and treating them isn't really a viable option for me, I've got a lot of montipora, some big colonies that I've had since I started with sps, and I really don't want to loose them.

Voyager2 wrote: ↑Mon Jan 27, 2025 1:44 am I caught sight of the black bugs in my tank last night, along with red bugs on my Acropora, and I decided to take action. I dosed Sentinel today, and I'm pleased to report that both the black bugs and red bugs vanished within 5 hours. I did notice a decline in my pod population, but given that I have a bare bottom tank, I wasn't too concerned about the biological impact.

From what I've gathered, many people have used Sentinel or Intercept without any major issues, and if I were in your shoes, I'd definitely consider using it. It might be worth exploring this option, especially if it could help you resolve the problem quickly.

I've got 3 structures made from reefplates, all rodded together and held with milliput. Two of these are bonded together, so we're talking serious weight here - around 28-35 kg each, and a whopping 70kg for the big one. It's designed to be a permanent fixture, specifically for fixing SPS in place. Let's just say, it's not exactly designed to be movable, lol.