Recently a stakepool (CRO) changed its costs and % fees 30 minutes before an epoch end, effectively changing the rules mid-epoch for people staking with the pool.

Are there other known stakepool attacks that affect the community and stakepool delegators at large?

Is there a service for notification on SPO rule changes mid-epoch?

  • IIUC it's possible to oversaturate a pool, but whether that counts as an attack is a bit dubious.
    – Mast
    May 9, 2021 at 15:35
  • I want to point out that they released a statement explaining that this increase happened after all delegators agreed. It was a private pool and the rewards should be used as a kind of donation, the delegators were probably promised some other kind of rewards. Of course, this was just one case and a dishonest pool operator could do this without having the delegators know and agree.
    – Peter1807
    May 9, 2021 at 20:46

2 Answers 2


In regards to the fee changes, this attack is somewhat mitigated by the protocol itself. Fee changes take effect in N+2 epochs. So, even if a pool operator raises their fees right before an epoch ends, the delegators still have 5 days to switch their delegation before those fees start to take effect. The attack on the Cardano Foundation's delegation was not successful because of this.

To be made aware of pool changes, I believe there are telegram bots from both adapools.org or pooltool.io and several other services that notify you of pool changes.


To answer your second question about tools notifying you about pool changes, you can try PoolTool Mobile.

From there you can set up Fee Change, Pool Saturation, and New Block mined notifications.

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