Purple Harlequin Rasbora eggs?

[Bking426]

Hi. I’ve had a few Rasboras for a month or so now. One looks very pregnant and I see something on the heater is it eggs or water bubbles? I’m a noob. I mostly just had betta until recently. TIA

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[Byron]

Those are bubbles of CO2 (carbon dioxide) which is often plentiful in tap water. I see this to varying degrees after water changes.