Well i never heard of a aquarium exploding and I certainly never experienced it either. You could check the aquarium by filling it up with water and put it in the bathtub for awhile to see if it is leak proof. How old is the aquarium? Also terrarium are wonderful to have. Maybe have a turtle in it. Also a 20 gallon tank is not all that big to cause any major mishaps.
theresa

An aquarium could explode if it´s custom made by someone who doesn´t know anything about how a certain thickness of glass could react to a certain shape, specially if it´s a tall one, the pressure that water generates over the glass is in direct proportion to the height of an aquarium, the taller the aquarium the more pressure the glass will suffer, just stay away from tall ones. A regular 25 gal aquarium is in no risk of exploding, normally they are manufactured with 6 mmm glass and the usual measurements for them are 30"L x 12"W x 16"H, 6 mm glass is strong enough for regular aquariums up to 55 gal. My recomendation for you would be in first place to stay away from those irregular shaped tanks like hexagons, they may look cool but it´s a pain in the neck to find filters, hoods and other aquarium essentials for them; in second place, avoid non regular aquariums, 20 gal is a good example, regular sized aquariums always have the same measurements, 10, 15, 25, 30, 55 gal aquariums are always the same, avoid aquariums like 20 gal long of 15 gal long, you won´t find a hood for them. A nice setup would be an "ALL GLASS" brand 25 gal with an "ALL GLASS" 25 gal hood, if you want an undergravel filter you can use a LEE´S 25/20 UG filter and it´s going to fit nicely in it, a 100 watt Visitherm heater/thermostat is what I would recommend and for more filtration a AquaClear 150 external power filter is more than enough. After you purchase your tank place it in the bathtub and fill it to check for leaks, I would highly recommend another hand of regular silicone caulk.

Your chances of having the water leak out is much greater than exploding but the resulting water damage would be the same. Buy a NEW tank from a reputable manufacture [All-glass, Perfecto] and you'll have years of trouble free operation. Be careful with filters, they can leak to. I had an external cannister hose pop off [my fault, not on tight enough]. Hang on's are pretty reliable. Chose a safe location where it won't get hit accidently. Make sure the tank is on a sturdy, level stand. Again, standard sized tanks are a bargin.

regarding "hoods"- i prefer the glass covers. they are much easier to clean. with a 20 long "all glass" you would use 2 of these. but, lights are purchased separately.

Well the 10 or 20 gallon Neno Cube glass aquarium kit has all the essentials.
Dual Cooling Fans
12 Gallon Glass Nano Aquarium
Built-in 3 Stage Filtration
JBJ 24 Watt Compact Fluorescent Lighting
50/50 (10k/Actinic) Bulb Included
Flip Top Canopy for Easy Maintenance
Dimensions: 15.8" x 13.8" x 14.8" (LxWxH)
6 Month Limited Warranty from JBJ Lighting

Here is a link that might be useful: {{gwi:374230}}

I did not mean 12 gallon glass but 20 gallon glass. I use to have a 70 gallon tropical all glass aquarium for 5 successful years. I do agree the bigger the better but since you have a landlord who doesn't really want you to have an aquarium because of fear of water problems, I was suggesting the smaller version aquarium or terrarium. Also you did not mention this gift of aquarium was handmade/custom, brand name or how old the tank is. If you decide to have gold fish in it, you probably will not need a heater because that type of fish likes cooler water then the tropical fish. On the other hand, tropical fish need to have consistant temperature so a heater and therometer would be needed. If you decide to purchase some fish, think about how big they will get in your size aquarium. Remember for every 1 inch size of fish equals 1 gallon of water for space. So it is important not to over load the tank with fish. More fish more waste, more toxin in the water. Also get a test kit and treatment to check your aquarium weekly or more often with new tank. A must is to have Stresscoat treatment for conditioning water. You will have to do water changes and cleaning on the tank. I did my 70 gallon tank, monthly. Let us know what you have decided. We each have had our own experiences of success and failures, that is why Gardenweb forum of many subjects is so helpful. We learn from each other and go from there. Good luck.
Theresa

Thank you all for your replies.

I forgot to put more details about the tank. It is an all glass tank. Dimensions are approximately 12" wide by 24" long by 16" tall. Altought I haven't measured it, I'm pretty sure the glass is 6mm thick. This makes it a regular tank. I don't know the brand. It was probably bought in a regular pet shop, not custom made, as it looks like all thos starter kits. It came with a hood that fits perfectly well on it. The hood includes the light and holes for the filter and water heater and a door to access the water for feeding. I really have no idea how old the tank is or how long it has been since last used. The silicone seems ok, not discolored, not damaged. I guess putting some more silicone is a good option, as suggested by raul.

I will test it for leaks.

Maybe the word exploding was a bit strong... It's just that I happenned to read the post abut the 100gallons tank exploding before writting mine.... That must have been quite something to clean up.

So... no one had bad leaking experiences? That's good to hear. It reassures me. I kind of got the idea that it was very common.

Thanks again
Vero

Well good luck Vero,
It sounds like you have good tank and with the added necessary precausions, you will be fine.
Enjoy,
Theresa

Before applying another coat of caulk clean it thoroughly and clean the old silicone with alcohol, alcohol removes oily films, dirt and debris, it leaves no residue and allows the new caulk to bond with the old caulk.

Tanks do not normally explode but if the tank is not placed on a secure stand they can do a good impression of one. I once had a twenty gallon on a dresser, everything was fine for about eight months and then one day the tank cracked across the back. If the stand is square and level it is very rare for a tank to leak or do anything else quickly. Put the stand where you want the tank and check the stand with a bubble level to make sure it is even from side to side and back to front. If the bubble is slightly off center from back to front or from one end to the other it is ok as long as it is the same on both ends or sides.

Another thought, make sure the tank is in a good location if this leak occurred, not to say it would. I would rather have overflowed water on tile floors then carpets. I usually put my tanks nearest to exit, such as glasss sliding doors to outdoors. That way you can siphone/vacuum the tank with hose going directly outdoors. Although I have heard that water is good for plants too so it could be siphoned into a barrel or bucket depending how big your tank is. Then give your plants a water treat.
Theresa

I havent ever had a tank break or explode and have had a lot over the last 20 years. only one has broke and it was my fault (long story). it was a 20 gallon tall and it covered an area of less than 10 sq. ft. radius. I used a wet/vac to get it up from carpet. had to allow it dry better before getting all the sand/gravel up.

but i have never had one break from normal use or set up and ive even tapped the glass to hard with rocks when rearanging or placing them in the tank. no cracks or breaks in 20 years other than the one i pulled over by accident when i was a kid.

just make sure that the stand is able to hold the weight and that its stable.

Someone got drunk and stumbled and fell on my ten gallon the other day,cracked the back glass.Luckily it didnt have any fish in it yet,and they had cleaned up the mess before I found out about it.Of course nobody knows what happened to it,just that it started leaking.My next tank is going to be alot bigger,and will not be located anywhere near a high traffic area.