Wait for the price to rise again then it will be allot better time to trade them.
In my opinion, investing bitcoin to altcoin is a good option to further increase your bitcoin holdings while waiting for your target selling price for bitcoin. There are people who want to accumulate more bitcoin in a span of time while waiting for it to increase. People will either buy more bitcoin which needs an additional funds or play in the altcoin ground where there is a possibility that their bitcoin will increase without adding additional money in the investment pool but rather have risk and face the possibility to lose bitcoin or gain it.