I usually Invest a very small amount of bitcoin to another coin because I know this time is very crucial to invest in any new coin or even in an old coin.
Any suggestion from your side which is good for long term
I would assume you then have much more than 1bitcoin in your portfolio. If not than I would move that bitcoin anywhere and just keep it. The market is too volatile right now to put it into anymore altcoins. You never want to have an unbalanced portfolio of alts to btc. I'd recommend a small fraction if your total go into these alts.
It would be a shame if the OP only had 1 Bitcoin in his wallet and was selling only for altcoins,
because Bitcoin still hasn't reached a new all time high,
it's better to sell half 0.5 Bitcoin and you can buy altcoins because with this strategy you can get x2 or even x10 profit in bitcoins and altcoins.