I have a small (probably 3-4 inch long) themomoter that is attached to the inside wall of the fish tank by a suction cup. This morning I found it broken.

I immediately removed the chards of glass and debris. The red bubble that presumably holds the mercury was still red; but the vile was completely broken. I did an emergency water change: about 30-40% (the tank is 135 US gallons).

I had to leave as I was late for work, so I couldn't observe the fish much. From what I could tell while I was conducting the water change, they were fine (a bit of a cut on one of the O's lip - likely the culprit of the mayhem!)

What should I do!? Are my fish going to die of mercury poisining? what about my biological colony in my filter?

I won't be replacing the thermometer - I'm going to use instant read from now on!

thanks in advance,
Meghan

There isn't enough mercury in one of those aquarium thermometers to cause any harm whatsoever so don't worry, it's happened to me on more than one occasion, that's why I don't use the internal thermometers anymore.

yup, ive had a couple break on me! now i use the floating type, and have it bobbing around inside my wier where the fish cant get at it lol. since mercury is so heavy, that lil bit is now probably down at the bottom glass at the bottom of your substrate, nothing you can really do about it either. changing the water wont take it out since its so heavy and under teh substrate now. it is a tiny amount tho so no worries about the fish's health, they should be just fine. you can do 50% waterchanges till the end of time, and that drop of mercury will still be in your substrate somewhere lol.

this problem has happened too my mate in the past and his oscars are still going strong so i wouldnt worry too much about it a little bit of mercury in 135 gallon really isnt nothin too worry about

just to clarify... if the stuff in the thermometer was silver... it was mercury... if it was red (most are now) its just dyed alchohol. in that case, you have absolutly nothing to worry about (aside from pieces of broken glass) as the alchohol will simply evaporate from the tank.

oh thank you everyone for the quick responses! what a relief! I seriously have been in a panic - thinking the worst. Wondering if I had to take the day off work, move the fish out of the tank, etc......

Doesnt everyone use digital thermometers... Glass thermometers seem a little outdated

My Oscars love chewing/ pulling on the digital probe... but steel is too strong for even them

Goob_Scooper wrote:


glass ones dont require batteries. and they cost about a $1.50 lol

I got home tonight and one of the O's has a cut lip - nothing bad; I'm sure it will heal fine. I used my net to dig out all the gravel at the breakage sight and found 3 or 4 more chards of glass.... glad I checked.

any suggestions for a non-glass/non breakable thermometer?

Win - I like your new photo!

Meh - I always go by the rule that a one of investment that saves me effort is always worth it As for batteries - my original ones have lasted me over 2 years now, and i never bother to turn it off...

has anyone tried one of the instant read types?

I have one of these - it's meant for food; but I don't see why I can't use it in the fish tank instead......

I just gave it a try and it took about 15 seconds to get a steady temp read.

MeghanR wrote:

ha ha ah...that would work well too... but it is more expensive than
the ordinary type thermometer. that thermoprobe is awesome and durable.
i used to use one when i work as foodtech research staff in a fast food chain