US spot bitcoin ETFs lost a net $64 million on Monday, even as spot ETFs for ether, XRP, Solana and Hyperliquid all pulled in fresh cash. On the surface, that looks like a clean rotation out of bitcoin and into everything else.Ether funds gained $22.5 million, Hyperliquid funds $17.2 million, and the XRP and Solana funds about $2.8 million each. That tracks Monday's price action, where the alts ran well ahead of bitcoin, with XRP up about 7%, Solana 6% and Hyperliquid 11% on the day. The flows followed the tape.It is worth keeping the scale in mind. Bitcoin ETFs still hold about $83 billion in assets, against roughly $10 billion for ether and around $1 billion each for the XRP, Solana and Hyperliquid products.The bitcoin number needs a second look. The outflow was not broad, as BlackRock's IBIT, the largest fund, actually took in $66 million. The net loss came almost entirely from Grayscale's GBTC, the high-fee legacy trust that has been shedding assets since these funds launched, which lost $124 million on the day. Strip out GBTC and bitcoin ETFs had an ordinary sessionThe real question is durability. If the altcoin ETFs keep drawing inflows once GBTC's drag fades, the rotation is real. If not, Monday was a blip dressed up as a trend.