How many bubbles from substrate does it take to actually cause harm?

[Wadikus]

Long story short, I am planning to rescape my 29G and was googling around to see whether or not I should remove my fish when i stumbled onto a slightly related topic of H2S in my substrate and the potential of gassing my fish.

I have about 3ish inches of Flourite Black Sand that is a little over 2.5 years running, I have MTS but I've never really "turned" my substrate in that time outside of gravel vaccing the first half inch or so. 

So out of curiosity I took my substrate sculptor and prodded around in a corner of my tank and sure enough some bubbles came up but I could not detect the "eggy" smell, will prodding around the rest of my substrate over the span of a week be harmful? I figured this would be a better way than lets say, rescaping and releasing it all at once.. I plan to keep the same substrate just want new rocks, wood etc.

The tank is well filtered with a tidal 75 and has an airstone, is there a way to combat a large release of H2S. I assume since the bubble makes it to the top in like half a second very little of it even makes it into the water?

Am i just being paranoid? I would hate to harm my fish but I am worried netting them all would be more stressful than doing a 3/4 rescape with them in the tank still.

[JettsPapa]

I wouldn't say you're being paranoid, but since you said you have MTS I doubt very much that you need to be concerned.  Besides, I won't say it never happens, but I firmly believe that the danger of toxic gases building up in substrate is often exaggerated.  I have a half dozen or so tanks set up with a mixture of dirt and dry cow manure capped with 2" of sand, and bubbles come up through it for months after setting up the tanks.  The fish, snails, and shrimp haven't seemed to mind.

[Wadikus]

Thanks, would you say removing fish to do a hardscape change is necessary or should i just do it with them in there?

and yeah I didnt notice any of the bubbles even smelling remotely like eggs and when I say I have MTS I mean... I GOT MTS lol, I try and cull them maybe once a week but they are legions!

[Matt B]

Anaerobic bacteria stinks!  😜  I'm Not saying it's a bad thing! My guess is anything in excess could do harm. 🤔  I've never seen it do harm. I wonder what others have experienced?   But they could use some deodorant or something....stinky little bacterias....🤣🤣

[Wadikus]

LOL yep!

Ultimately I only have 3 small and midsized tanks and I always try to do right by my fish.. and since experience is the best teacher I try and reach out for some wisdom from those who have had experiences with this is the past.

 

[JettsPapa]

On 6/26/2024 at 2:55 PM, Wadikus said:

Thanks, would you say removing fish to do a hardscape change is necessary or should i just do it with them in there?

and yeah I didnt notice any of the bubbles even smelling remotely like eggs and when I say I have MTS I mean... I GOT MTS lol, I try and cull them maybe once a week but they are legions!

I'm of the opinion that netting fish out of the tank, moving them to a temporary container, and then netting them again and putting them back in the tank after you're finished stresses them at least as much as, and probably more than, just leaving them in the tank.