I've sent some BTC with a low fee..
0.0000001 is not a low fee, it is an invalid fee that will cause your transaction to be immediately discarded by any nodes or miners receiving it. You will need to remove the record of this transaction being sent from your own wallet to restore the balance shown to you, and then switch to a wallet that doesn't let you do silly things.
Hm, what's the criteria for validity?
It doesn't look discarded as blockchain.info sees it. Anyway, how do I remove the record of this transaction from wallet?
The wallet I'm using is bitcoind.
It seems your input is very old so you could send the tx practically without fee. You may wait few days just in case it gets added to blockchain