Altcoins re coins other than Bitcoin. It's gotten from the description given to coins that are the alternative for Bitcoin, since Bitcoin is now more expensive than people would imagined they created alternative coins hence the name ‘altcoin’ and since these coins are available on several exchanges like Quidax, I'll say yes, altcoin trade exist, and it's ow safer than ever before. Here for example, if you do not share your details with anyone online and offline, there's nothing like hacking of funds and assets as reported on other platforms where there's a very high risk of theft.

To pick the good altcoins that's out there, you can look upto Coinmarketcap or coingecko to read more on the altcoins before invest; also, remember that altcoins are also very volatile sonce they're still the same cryptocurrencies. Be more security conscious and vigilant, don't share your private keys or login details with anyone and don't click on links you do not know, also anyone or platform telling you to connect your wallet to any website for a tighter security is only trying to steak your funds, be safe out there.