Bitcoin hit a five-day high this morning after the Federal Reserve left US interest rates near zero — but the rally quickly fizzled.

BTC spiked to as much as US$38,825 immediately after the 6am AEDT announcement, but by lunchtime had faded to just US$36,900, up 0.7 per cent from yesterday.

Ethereum spiked as high as US$2,727, its best level since Saturday, but by midday had fallen to US$2,418, down 0.9 per cent from yesterday.

Overall the crypto market was up 0.1 per cent to US$1.75 trillion as the market digested the news. Fed chairman Jerome Powell told reporters that a rate hike would likely come at the central bank’s March meeting, with subsequent increases to follow at a pace still to be determined.

About 10 of the top 100 cryptos were up and the rest were down.

Arweave was the biggest decliner, falling 10.4 per cent to $29.56.

Theta Fuel had posted the most gains, rising 24.8 per cent to 16.1c.