All aquaria today are constructed of tempered glass, with silicone seals and plastic frames, or entirely of clear acrylic. This is exactly the way they should be constructed, and it is hard to go wrong with a new tank. If possible, you should leak-test a new tank for a few days outside or somewhere where a little dripping water will do no harm, but the incidence of leakers is really very low. If you use cold water, expect condensation all over the glass until it warms. This is not leaking; just dry it off with a towel. Aquarium glass will scratch. You should always be gentle when moving the gravel or stone decorations inside the tank. Acrylic scratches very easily, and for this reason, along with the high cost, I would avoid it.
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