Blackhole swap routes: when lower fees lose to shallow pools

A Blackhole swap route trades pool fees against price impact, so the cheapest-fee path may deliver less of the token you want. The deciding figure is the output after fees and price impact for your trade size, not the fee rate viewed alone.

Blackhole’s docs describe three automated market maker types: concentrated-liquidity, classic UniV2-style and stablecoin pools. Each has different liquidity and pricing mechanics; a pool’s displayed balance does not necessarily show how much is available near the current price. For a walkthrough of the trade flow, see Blackhole swap steps for Avalanche trades.

How do fees and pool depth affect a swap?

A pool fee is charged on a swap through that pool, while price impact comes from the trade moving the pool’s price. Blackhole says traders pay swap fees that incentivize liquidity, and its docs describe pools with different AMM models. The fee and depth can therefore vary by route.

In a shallow pool, a large order uses more of the available liquidity and can move the price further against the trader. A deeper pool may charge a higher fee yet produce a better final output because the trade creates less price impact. For a multi-hop route, each pool adds its own fee and another point where liquidity can affect the price.

When can a multi-hop route beat a direct pool?

A multi-hop route can improve the result when its pools together offer better prices and depth than the direct pair, even after fees from every leg. It can also lose: extra fees accumulate, and a thin intermediate pool can erase the benefit of routing through it.

Concentrated liquidity adds another constraint. Liquidity providers choose a price range, so only liquidity active around the current price helps execute a trade. A pool may look large in total, but if little liquidity sits near the trading price, a sizable swap can still face material price impact.

Compare the displayed output for the same input amount and settings. If the interface shows a route breakdown, check the pools and hops; a lower fee on one leg does not establish that the full route is cheaper. Also distinguish the pool’s swap fee from any network transaction cost shown separately.

What should traders check before signing?

Use the quoted output after fees as the main comparison, then inspect the route for costs or risks the headline fee hides. For a volatile or newly launched token, recheck the quote immediately before signing: pool balances and prices can change between quote and execution.

• Compare final output for the same input and slippage setting.
• Check each hop’s pool and fee, where the interface provides that detail.
• Look for price impact as well as the fee rate; shallow active liquidity can dominate the cost.
• Set a slippage limit that fits the trade, and cancel if the expected output changes beyond it.

For most trades, choose the route with the strongest quoted output at an acceptable slippage limit, not simply the lowest displayed pool fee. Review the quote again just before confirming the transaction.