How Big Bass Bonanza works

The base game is the straightforward part: a 5×3 reel layout with 10 fixed paylines, paying left to right on adjacent reels from the leftmost reel.

It’s mostly the platform for the feature. Once Free Spins begin, two collection systems run at the same time. Money Collection pays out the Fish values on a single spin, while Symbol Collection counts how many Fisherman Wilds have landed across the whole feature.

The count sits along the top of the screen and lights up as it fills. That’s the part I like most, because it reminds me of the feature trails on UK pub fruit machines.

How Free Spins start

Three or more Scatter symbols trigger Free Spins. The more Scatters, the more spins you start with:

How the Fisherman collects Fish Money

During Free Spins, Fish Money symbols can show values of 2×, 5×, 10×, 15×, 20×, 25×, 50× or 2,000× total bet.

The Fisherman Wild.

When a Fisherman Wild lands, it collects the value of every Fish Money symbol on screen, multiplied by whatever collection multiplier is active at the time.

A Fish on its own pays nothing, however big its value. If no Fisherman lands on that spin, the Fish values aren’t collected.

When more than one Fisherman lands

Two Fishermen don’t share one catch. Each collects the full total on screen.

Pragmatic Play’s own overview gives the example: if the Fish on screen add up to 100× and two Fishermen land, you get 100× twice, before the multiplier is applied. Both Fishermen also go towards the count.

The Fisherman count and retriggers

Every Fisherman Wild that lands is added to the count, and three points on it matter: the 4th, 8th and 12th Fishermen.

Each of those points adds 10 Free Spins and moves the collection multiplier up a step. That’s the game’s retrigger system, and the extra spins are queued to play after your current batch ends.

The count doesn’t reset when it reaches four. It keeps going to eight, then twelve, and twelve is the last step, so there’s no fourth stage.

What the multiplier applies to, and when

The increasing multiplier only applies to what the Fisherman collects from the Fish. Ordinary payline wins aren’t multiplied.

It also doesn’t apply straight away. The new multiplier kicks in with the 10 extra spins, after your current spins run out, and stays until the next step up or the end of the feature.

What Dynamite actually does

Dynamite can appear when exactly one Fisherman lands and there are no Fish Money symbols on screen. Some positions then turn into Fish Money symbols.

It looks as though the spin is changing after the fact, but it isn’t. Pragmatic Play’s developer material describes the Fish positions as already part of the result (it calls the mechanic SymbolReplacement). The Dynamite is just how the game reveals them, not a second chance after the spin has finished.

Big Bass Bonanza RTP: four settings at 11 UK casinos

There isn’t one RTP for Big Bass Bonanza. Pragmatic Play’s current data lists 96.71%, 95.67% and 94.50%, and UK certification documents add 94.02%, 92.05% and 90.63%. To see which ones casinos actually use, I checked the game at 11 UK casinos on 24 and 25 September 2026:

Five showed 94.02%, which makes it the most common setting here, but 11 casinos are a sample, not the whole market. I didn’t find 95.67% or 90.63% anywhere.

That spread surprised me. For a game this popular, 92.05% to 96.71% is a big gap. In theory, at 92.05% you’d expect to lose £79.50 for every £1,000 staked over the long run, and at 96.71% it’s £32.90. That tells you nothing about a single session, but it is a real difference in what the game costs to play. I don’t think most players realise that UK casinos choose such different settings for the same game.

The results for all 13 games I checked are in my RTP study.

Low or High volatility? The sources disagree

Pragmatic Play’s current data and the game’s current rules call Big Bass Bonanza Low volatility, and all 11 UK casinos I checked showed Low too. The rule sheets for the UK, Sweden and Spain say High, though, including the UK one.

I can’t tell from the documents whether that’s a different version of the game or a label that changed over time, so I’ve kept both. Either way, a volatility label is the developer’s description, not something that predicts a session.

Hit frequency

Pragmatic Play’s current data lists base-game hit frequency as 1 in 7.69 and Free Spins hit frequency as 1 in 113.

Both are long-run averages from the supplier. They won’t tell you what will happen in a particular session.

The 2,100× maximum win

The maximum win is 2,100× your bet. If Free Spins reach it, the feature ends straight away, you’re paid the capped amount and any spins left are lost.

So don’t multiply the big numbers together. A Fish can show 2,000× and the multiplier can reach 10×, but nothing pays more than 2,100×.

Stakes and Feature Buy in Great Britain

In Great Britain, the most you can stake on an online slot is £5 a spin if you’re 25 or over and £2 if you’re 18 to 24. Casinos can set lower limits.

All 11 casinos I checked showed a £0.10 minimum and £5.00 maximum bet in the game rules. That on-screen £5 doesn’t override the £2 limit for 18 to 24 year olds. Older UK rule sheets mention a £250 maximum, but that’s out of date.

The original game has no Feature Buy or Ante Bet, and Feature Buy isn’t offered on GB-licensed slots anyway. There’s more in the Feature Buy guide.

Release date and the follow-ups

Pragmatic Play launched Big Bass Bonanza on 14 December 2020. Some UK casinos show jackpot strips or promotions around the game; those come from the casino, not from the game’s own rules.

This guide covers that original game. Big Bass Splash and the other follow-ups have their own rules and RTP settings, so don’t assume these numbers carry over. There are a lot of them now, in different themes at different times of year. I can only assume Pragmatic keeps making them because operators ask for them: it’s a brand players recognise, and operators want games that attract players, so it’s self-fulfilling. They’re riding that horse all the way, and if I’m honest, I think there are too many.